4 Natural Remedies to Help You Quit Smoking

4 Natural Remedies to Help You Quit Smoking More in Addiction Nicotine Use How to Quit Smoking After You Quit Nicotine Withdrawal Smoking-Related Diseases The Inside of Cigarettes Alcohol Use Addictive Behaviors Drug Use Coping and Recovery Smoking is one of the most difficult addictions to overcome, so its only natural that you want to try anything that might help. Many smokers look to natural remedies to help them quit, but not all of them are effective or actually safe for you to use. When youre seeking natural alternatives to help you quit smoking, there are a few that you might try. There are no guarantees that they will work, however. Many people who successfully quit used multiple approaches, including counseling or a support system. Acupuncture Acupuncture is a common therapy  that some people use to help them quit smoking. The acupuncture needles used are usually hair-thin. They are inserted into various points in the ear where they remain for about 20 minutes. For help in between sessions, many acupuncturists provide tiny balls (the size of the tip of a ballpoint pen), that are taped with invisible tape to the ear. When a craving for cigarettes hits, the smoker is instructed to press gently on the ball, which stimulates the acupuncture point. One five-year study in Hong Kong of 5,202 smokers concluded that acupuncture was both an effective and safe method to help smokers quit. The study notes that the number of cigarettes per day decreased and that the average time to relapse was 38.71 days, which was longer than 35 days in E-cigarette and 14 days in nicotine patch.?? The number of acupuncture sessions made a significant impact on success, with most people receiving eight sessions within the first month. St. Johns Wort The herb St. Johns wort (Hypericum perforatum) is used primarily for depression. Researchers have been trying to figure out if its effective for smoking cessation as well. The results are mixed.?? Although St. Johns Wort appears to be reasonably safe when taken alone, it can interfere with the effectiveness of prescription and over-the-counter medications. This includes antidepressants, drugs to treat HIV infections and AIDs, drugs to prevent organ rejection for transplant patients, and oral contraceptives.?? St. Johns wort is not recommended for pregnant or nursing women,?? children, or people with bipolar disorder, or liver or kidney disease. Ginseng Ginseng has been shown to prevent the nicotine-induced release of the neurotransmitter dopamine.?? Dopamine is what makes people feel good after smoking and is part of the addiction process. Although intriguing, no studies to date have examined whether ginseng supplements can help people quit smoking. Hypnotherapy The next question many people have is whether hypnotherapy can help. It sounds like a good alternative to prescription and over-the-counter stop-smoking aids, but is it effective? According to one randomized trial, hypnotherapy is only slightly more effective than behavioral relapse prevention intervention. After three days of not smoking, participants were placed in one of the two groups. The hypnotherapy group had a 29% success after one year, while 28% of people in the counseling group had quit.?? In another study, hypnotherapy was compared with common nicotine replacement therapies (NRT). The two were also combined for some of the hospital patients in the study. The methods were used and followed after the participants were discharged from the hospital. The conclusion was that hypnotherapy was more effective NRT in long-term abstinence, though there was no improvement when the two therapies were combined.?? Lobelia Is Not Recommended The herb lobelia (Lobelia inflata) has been promoted to help people fight the effects of nicotine withdrawal and it is found in many anti-smoking products. The active ingredient in lobelia is lobeline and it is thought to have similar actions on the body as nicotine. In 1993, however, the U.S. Food and Drug Administration (FDA) temporarily prohibited the sale of certain lobelia products marketed to help people quit smoking. According to the report, the reason was that evidence showed they were not effective.?? Lobelia has since been placed on a list of smoking cessation ingredients that require FDA approval. Later research has shown that lobeline may increase levels of the neurotransmitter dopamine in the brain, an effect similar to cigarettes. Dopamine influences mood and produces feelings of pleasure. There is still no evidence, however, showing that lobelia supplements help people quit smoking.?? Lobelia is a potentially toxic herb, however, so it cannot be recommended.  It is also in the FDAs Poisonous Plant Database. Lobelia can cause dry mouth, profuse sweating, nausea, vomiting, diarrhea, tremors, rapid heartbeat, confusion, seizures, and coma. In larger doses, it can even cause death.?? People with heart disease, high blood pressure, heart disease, tobacco sensitivity, paralysis, seizure disorder, shortness of breath, or who are recovering from shock are at particularly high risk. Pregnant and nursing women and children should never take lobelia. A Note From Verywell Scientific support for the claim that any remedy can help with smoking cessation is limited. Supplements havent been tested for safety and are largely unregulated. This means that the content of some products may differ from what is specified on the product label. Also, keep in mind that the safety of supplements in pregnant women, nursing mothers, children, and those with medical conditions or who are taking medications has not been established. If youre considering the use of any form of alternative medicine, talk with your primary care provider first.

The Recipe for a Happy Marriage - 635 Words

America is the land of the free and home of the brave. As American citizens, we enjoy exercising our liberties and fighting for what we believe in. This includes freedom in regards to romance, love, and marriage. Yet, sometimes our cultural backgrounds and family interfere with our given liberties. Movies, and other forms of artistic expression, often point out societal flaws and bring to light underlying issues. Comedic expression is a popular way to get across serious points, because the audience is more receptive to humor and happiness than anger and sadness. It is just like the old adage â€Å"you catch more flies with honey than with vinegar.† This is why we see big issues of politics, materialism, environmentalism, and so forth taken to the screen to reach a larger audience. For example, the movie Supersize Me successfully brought attention to the negative health and environmental impact of fast food chains. Even though the movies It Happened One Night and My Big Fat Gre ek Wedding are decades apart, they both bring attention to the underlying concerns for how young people meet and fall in love. Cultural background, ethnicity, and socioeconomic status are factors in determining a socially acceptable couple. This can unfortunately perpetuate racism through endogamy. Endogamy requires people to marry within their own group. In America, we are a melting pot of cultures, and sometimes cultures will demand their members marry only members of the same background. In My Big FatShow MoreRelatedThe Role of Food and Recipes in Like Water for Chocolate by Laura Esquivel1140 Words   |  5 PagesThe role of food and recipes in Like Water for Chocolate by: Laura Esquivel From the time of Adam and eve, food is always a very essential need of human life. Due to good or bad eating habits and the difference in human body sizes is always noted. Eating a lot does not guarantee good health as eating balanced diet. Many individual eat certain groups of foods mostly due to their cultures, backgrounds, geographic locations and also the economic status of their families and their ethnic groups. UnlikeRead MoreThe Likeliness of Being Different1504 Words   |  7 Pagesbecause of that everything that happens in during our lifetime is a contribution to our development as human beings. Frances Klagsbrun s article Long-Term Marriages tries to explains the secrets being long lasting marriages. The article resembles our first assignment where we had to go out and interview couples about their marriage recipe. Klagsbrun clearly writes from a North American point of view. She divides the â€Å"secrets† into eight categories: an ability to change and tolerate change, anRead MoreDivorce Is More Popular Than Marriage868 Words   |  4 Pagespopular than marriage. As soon as you say,† I do,† the odds are not in your favor. 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Chopin uses the conceit of a thunderstorm to describeRead MoreIs Meat The New Ring?1605 Words   |  7 Pagescall to self-awareness (Britannica). Based off the short biography, Rosario Castellano’s â€Å"Cooking Lesson† is the perfect postmodern piece of writing to discuss for three reasons. The first being throughout her entire â€Å"Cooking Lesson† she ponders a â€Å"recipe† to debunk stereotypical upper middle class gender roles, like being a â€Å"society matron†, later refuting her claims by sprinkling hints of feminist sarcasm through her internal monologue. She specifically does this by referring to a wife’s role as

The Speech To The Virginia Convention Rhetorical Analysis

Rhetorical Analysis of Henry Outline Introduction Attention getter- Thesis- The rhetorical devices in the Speech to the Virginia Convention by Patrick Henry is very effective. Appeals Emotional Context and quote- This quote appears during Henry responds to the opposing argument, giving reasons to refute it. â€Å"There is no retreat, but in submission and slavery! Our chains are forged! Their clanking may be heard on the plains of Boston! The war is inevitable and let it come! I repeat it, sir, let it come† (82). Effective- Henry is mentioning the motif of slavery. He exclaims how the colonies would essentially become prisoners under the control of the British. He uses the word â€Å"clanking† to appeal to pathos to create the horrid images†¦show more content†¦Use of Language Allusion Context and quote- Henry makes an allusion to Homer’s Odyssey during his speech in the Virginia Convention. â€Å"We are apt to shut our eyes against a painful truth, and listen to the song of that siren till she transforms us into beasts† (81). Effective- In The Odyssey, Odysseus’ men fall asleep while listening to the soothing singing of the siren Circe, who then transforms each of the men into beasts. Henry uses this allusion to compare the well-known book to the state of affairs between the colonies and Great Britain. His goal is to convince the colonial leaders that they have no choice but to fight against the British. Henry wants to ensure that the colonists do not remain idle while the British transform them into beasts. The colonists needs to take action and fight for their freedom. Restatement Context and quote- Henry is describing how powerful and great the army of the colonies could be if they attempted. â€Å"The battle, sir, is not to the strong alone; it is to the vigilant, the active, the brave† (82). Effective- Henry uses restatement to stress the importance of the impending war. He feels strongly that a war is needed because the colonists must fight for their freedom. War isn’t only for those who can and will fight, it’s for anyone who wants a better life. The battle is for the brave people, and the ones who are ready for danger, and are active. Because theyShow MoreRelatedRhetorical Analysis Of Speech To The Virginia Convention863 Words   |  4 PagesPatrick Henry, a speaker at the Virginia Convention, proclaims, â€Å"I know not what course others may take; but as for me, give me liberty or give me death!† (Henry 7). In an attempt to allure a congregation with antithetical perspectives, Henry urgently supplicates for the proclamation of war in opposition to the British rule. After acknowledging the multiple accounts of unjust occurrences against the colonists, he implores the individuals in his audience to confront the inconsiderate government. TheRead M oreRhetorical Analysis Of Patrick Henrys Speech At The Virginia Convention807 Words   |  4 Pages Patrick Henry Rhetorical Analysis In 1775, the citizens of colonial America were under distress due to the pressure coming from Great Britain. The citizens wanted liberties, however, the country as a whole was reluctant to push the issue to a point of initiating war. 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Then, we willRead MoreRhetorical Analysis Of Patrick Henry s Speech1341 Words   |  6 PagesRhetorical Analysis of Patrick Henry’s Speech in the Virginia Convention (Brainstormed with Caroline Schwanawede, written independently) Amid the early conflicts between the American colonists and the British government, in addition to their supporters, these two groups experienced the difficult reality of colliding with an opposing set of values and lifestyles to their own, leading to mutual feelings of hostility and resentment and establishing a widespread want for a revolution in the colonialRead MorePatrick Henry s Give Me Liberty1784 Words   |  8 PagesPatrick Henry’s â€Å"Give me Liberty, or Give me Death:† A Rhetorical Analysis On March 23, 1775, in the meeting hall of St. John’s Church in Richmond, Virginia, a group of important statesmen, merchants, plantation owners, military leaders, and various others met to determine the fate of their beloved colony. The colony of Virginia, under the governorship of Lord Dunmore, was tearing at its seams between monarchists, who remained loyal to the British Crown, and patriots in support of independence. Read MoreLiberty or Death1755 Words   |  8 Pagesaudience to fight for freedom. Through the use of rhetorical strategies, Patrick Henry was successful in convincing the colonies to fight for their freedom from Britain and Malcolm X was successful in convincing African Americans to fight for their rights. To begin with, Patrick Henry was one of the first opponents of British rule in the colonies. He was famous for giving speeches on American Democracy. Patrick Henry’s wit, eloquence, and rhetorical gifts made him a great orator. He eventually becameRead MoreRhetorical Analysis Of Patrick Henry s Speech1375 Words   |  6 PagesEnglish 1101 November 11, 2016 Rhetorical Analysis: Give Me Liberty or Give Me Death! Many men were pivotal to the American cause in the War for Independence, and one of the most influential was Patrick Henry. In his famous speech â€Å"Give Me Liberty or Give Me Death† Patrick Henry delivered a powerful speech through the manipulative use of language and word choice. On March 23, 1775, the third Virginia convention was held in St. John s Church in Richmond. The convention was held to discuss relationsRead MoreComparison of Thomas Paine and Patrick Henry: Revolutionary Tract876 Words   |  4 Pagesthrough providing reasoning and evidence that moved many colonists to believe that to reach contentment and peace the colonies had to rid themselves of British rule. Henry and Paine were successful in swaying their audience, not only because of the rhetorical strategies used, but also because they were passionate about the cause they were committed to. Both Paine and Henry tried to push for support against Great Britain and motivate the colonists to side with the revolutionaries. Both felt obligatedRead MoreSlaves Narratives: Frederick Douglass, Olaudah Equiano Essay1477 Words   |  6 Pagesher religious life, become apart of the abolitionist movement, and give public speeches. Truth wrote a well-known personal experience called An Account of an Experience with Discrimination, and she gave a few famous speech called Ain’t I a Woman? and Speech at New York City Convention. In 1818, Frederick Augustus Washington Bailey was born into slavery in Tuckahoe, Maryland. When he was older, he made an escape plan by disguising himself as a sailor and going on a train to New York. When he becameRead More The Life and Political Career of James Madison Essay4338 Words   |  18 Pageshis bookish nature, Madison spent the years prior to the American Revolution studying† where he â€Å"resumed his investigations of governmentâ €  (Sheldon 25). Through these investigations, â€Å"Madison found himself being drawn down into the real turmoil of Virginia politics, inflamed by the impending revolution† (Sheldon 26). Madison’s high education and religious morals later shaped his political career, while his own ideas center around a religious emphasis. Garrett Sheldon, who specializes in political

The Virgin of Vladimir Free Essays

http://www. flickr. com/photos/t-a-a/5340663023/  Ã‚  Ã‚   The Virgin of Vladimir Byzantine painting was not realistic in its representations of the divine and super natural. We will write a custom essay sample on The Virgin of Vladimir or any similar topic only for you Order Now (Online Lectures) The final results were paintings and mosaics that had a blending of some naturalistic elements and abstractions. (Online Lectures) The unifying element was that the works were depictions of the Divine for the Church. (Online Lectures) The Virgin of Vladimir an image depicting a mother and child was given to the Russian ruler by the Byzantine emperor somewhere between 1130 and 1135. This image later became known as the Virgin of Vladimir which is believed to have been one of St. Luke’s original paintings painted from real life. (Unknown) As of today it is now considered to be the work of a twelfth century Byzantine artist, to date its true creator is still unknown. This icon has come to be considered the most important and most powerful icon in Russia. (Unknown) This is one of the most copied icons over generations. This icon was credited with protecting Russia in several battles. F. S. Kleiner) Because of this, the Virgin of Vladimir was held in close regards by rulers of Russia. (Unknown) Whenever the capital moved, the icon moved as well. It eventually ended up in Moscow in the late fifteenth century. The Virgin, as seen in the example image that I choose, is holding the child in a tender embrace while looking out to the viewer. It has been said that she is acknowledging Christ’s future sacrifice for all of mankind. This image exhibits all of th e characteristic Byzantine traits: her straight long nose and small mouth, the golden rays in the infant’s drapery; the decorative sweep of the unbroken contour that encloses the two figures; and the flat silhouette against the golden ground. †   (F. S. Kleiner)   This work of art is unified. The artist used actual proportions in this painting; the child is proportionally smaller than the mother. The vividness of the hues of yellows and oranges worked well creating a harmonious piece of art. Overall, I think that this is an interestingly balanced piece of art. Works Cited Kleiner, Fred S. and Mamiya, Christin J. Gardner’s Art Through the Ages: A Concise History of Western Art. Belmont, CA: Wadsworth Publishing, 2007. â€Å"Byzantine Art. † Online Lectures: History of Art in Early Civilization ART1020 XD. Web. 3 September 2011. Unknown. Art Through Time: A Global View . unknown unknown unknown. 4 September 2011 ;http://www. learner. org/courses/globalart/work/219/index. html;. How to cite The Virgin of Vladimir, Papers

Supply Management free essay sample

E)Monthly conferences 34. The effect of different materials on productivity and cost is often the result of: A)Using less costly materials B)Using the latest hi tech materials C)Using computer run machines D)Using more costly materials E)Faster delivery of the materials 35. Which of the following is not a step in the â€Å"Six-step Environment Monitoring Strategy† presented in Chapter 3? A)Identify the major suppliers and customers of the materials and services. B)Build a model that predicts the material (or service) behavior. C)Monitor the model to determine its accuracy. D)â€Å"Run quantitative models to confirm your strategy† E)Continuously make improvements as new relationships are understood and additional data becomes available. 36. In the introductory case at the beginning of Chapter 3, Ted Jones, supply manager for the Eagle Manufacturing Company, expressed his concern about the issue of adequate lead-time for the purchase of a new robot. How much does the lack of adequate lead-time cost in the case? A). We will write a custom essay sample on Supply Management or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page 5 million B)$1. 7 million C)$12. 7 million D)$11 million E)None of the above 37. Why does supply in non-manufacturing organizations have as much impact on profits as it does on manufacturing firms? A)The global nature of services B)Competition in the service industry C)The nature of personal services D)Type of suppliers E)In the absence of engineering departments, supply management must often be the leader in determining requirement 38. Which one does not contribute to the potential conflict between design engineers and supply management professionals? A)Supply managers are only interested in the bottom line B)Engineers naturally tend to design conservatively C)Engineers usually disregard cost or availability D)Supply managers are concerned with cost and availability E)Both differ in their concepts of material 39. What should be the relationship between supply management and logistics? A)Logistics department plays the dominant role B)Supply management plays the dominant role C)Professional and excellent regardless of their task D)No relationship E)An adversarial relationship 40. What approach should attorneys who are involved in supply management embrace? A)Transactional B)Aggressive C)Conservative D)Collaborative E)Adversarial 41. the many internal interfaces of the supply management function begin with: A)Engineering B)Material control C)The customer D)Operations E)Production Control 42. One of the key reasons for a proper interface between design engineering and supply management is: A)Early supplier involvement can reduce design costs and time to market B)It reduces conflict on specifications C)It helps reduce inventory D)It improves ROI E)It improves quality

The Mechanism of the Paterno-Buchi Reaction and its Application in the Organic Synthesis Review

The Mechanism of the Paterno-Buchi Reaction and its Application in the Organic Synthesis Review Free Online Research Papers The Paternà ²Ã¢â‚¬â€œBà ¼chi reaction, named after two chemists who established its basic utility and form, is a photochemical reaction that forms four-membered oxetane rings from a carbonyl and an alkene. Much work has been done with the reaction since Dr. Thorsten Bach of the University of Marburg published a review article in 1998 on its mechanism and synthetic utility. The Paternà ²Ã¢â‚¬â€œBà ¼chi reaction has been used recently in attempt to synthesize many natural organic products. In these experiments, the chemists are chiefly concerned with the regio- and diastereoselectivity of the products. This paper will address these selectivity concerns and report on the specific products that have been worked with since Dr. Bach’s 1998 review paper, such as (+)-Preussin and (?)-Oxetin. The following review seeks to be a source of information detailing the recent discoveries in the mechanism and application of the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction, intended specifically for organic chemists involved in synthesis. Contents Abstract I. Introduction†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 3 II. Mechanistic Knowledge and Recent Discoveries A. General Mechanism†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 5 B. Mechanistic Issues in Synthesis 1. Regioselectivity†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 7 2. Stereoselectivity†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. 8 III. Specific Synthetic Applications A. Ring Opening Reactions†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 11 B. Formation of Natural Oxetane Products†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. 13 IV. Summary†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 13 V. Literature Cited†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.. 15 VI. Tables†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. 18 VII. Figure Captions†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. 20 VIII. Figures†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 21 IX. Schemes†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦. 23 Introduction Photochemistry is the study of chemical reactions that are affected by or proceed upon application of light energy. Photochemical processes are useful tools in the laboratory because they excite ground-state electrons and form radicals.1 These radicals can be used to add to other molecules to form products that would be impossible or at least more difficult to form using other synthetic methods. The Paternà ²Ã¢â‚¬â€œBà ¼chi reaction is a synthetic method used in photochemistry that forms oxetane rings through excitation of the electrons on a carbonyl molecule. When the electron on the carbonyl is excited, it forms a radical and adds to an alkene, forming a 1,4-diradical. The diradical then closes and forms the oxetane ring when the two excited 1,4 electrons combine (see Scheme 1). An oxetane is a four-membered cyclic molecule (or part of a molecule) composed of three carbon atoms and an oxygen atom (see Figure 1). The configuration of the product oxetane and the diradical explanation of the mechanism were established by Dr. Paternà ² and Dr. Bà ¼chi. The Paternà ²Ã¢â‚¬â€œBà ¼chi reaction was named for these two chemists. Their work was published separately; Dr. Paternà ² published his article in Italy in 1909, and Dr. Bà ¼chi’s article was in print by 1954.2 Since 1954, chemists have produced several additional reviews of the reaction. These reviews have only recently begun to appear in the literature; most have been published within in the past 20 years.1 In 1998, Dr. Thorsten Bach of the University of Marburg wrote one of the most comprehensive review articles concerning the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction. The review explained the mechanism of the process based on the information available from previous experimentation. Dr. Bach’s paper then continued to detail the specific products that can be synthesized using the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction. Much of his work addressed the concerns in regio- and stereoselective yield that arise during photochemical synthesis.1 Understanding the factors affecting regio- and stereoselective yields and other aspects of the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction mechanism would greatly aid chemists in their effort to synthesize natural compounds and other organic products. Many of these products have oxetane rings in their structure, and several others are alcohols that can be synthesized using the Paternà ²Ã¢â‚¬â€œBà ¼chi process followed by a ring-opening reaction. In either case, an understanding of the mechanism of the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction will aid chemists in obtaining yields with high selectivity.1,3 The selectivity of the yield in a synthetic process is especially important during manufacture of biological compounds, where the regio- or stereochemical structure of a drug can mean the difference between recovery and fatality. Regio- and stereochemical control can be achieved using the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction, which provides more efficient and sometimes essential methods of synthesizing many important biological products. The ?-amino acid oxetin, which acts as an antibiotic and herbicide, and the antifungal agent (+)-Preussin are two examples of natural compounds that can be made using the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction.4,5 Experiments concerning the synthesis of natural compounds have been recently growing in number. Since the printing of Dr. Bach’s paper in 1998, there have been several such experiments involving the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction, and publications reporting the regio- and stereoselective issues and mechanics of the process have appeared in numerous journals. Regardless of the specific interest in the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction or photochemistry in general, chemists who are involved in organic synthesis would benefit from the latest knowledge of an efficient synthetic method.5 This review paper, intended then for organic chemists involved in general synthesis, will seek to compile the experimental results of only those publications in print since Dr. Bach’s review article. Mechanistic Knowledge and Recent Discoveries General Mechanism The Paternà ²Ã¢â‚¬â€œBà ¼chi reaction involves promoting electrons into excited states with light and allowing them to form cyclic bonds. The reaction is a type of [2 + 2] photocycloaddition, or 2? + 2?, which indicates that two electrons in ? bonds are reacting with two other ? electrons to form two different bonds. The two ? bonds in the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction come from a molecule containing an alkene component and a molecule with a carbonyl component. The new bonds formed through this process are ? bonds. Because these ? bonds complete a ring, the reaction is called a cycloaddition. Adding the â€Å"photo-† prefix to the word â€Å"cycloaddition† indicates that the reaction is initiated by light energy.1 When enough light energy is applied to the carbonyl group, an electron in either the nonbonding orbital or the ? bond enters into an excited state wherein the electron is promoted to an anti-bonding orbital (see Scheme 1).6 The promoted electron initially retains its spin, and because electrons in the same orbital have opposite spins, the excited electron and the electron with which it was coupled before excitation still have opposite spins. This electron configuration is known as an excited singlet state, which is abbreviated and represented in Scheme 1 as S1. However, the S1 does not last long (approximately 1–2 ns), and the spin of the promoted electron quickly changes. This situation, in which the promoted electron changes its spin, is called intersystem crossing, or ISC.1 In this case, the excited electron goes through ISC from the S1 to the triplet state, abbreviated T1.6 The initial addition to the alkene 1 can happen either in the T1 or S1. If the carbonyl remains in the singlet state long enough to add to the alkene, it will add to form a transition state resembling a 1,4-diradical 3 with a negligibly short lifetime. The brevity of the lifetime of this diradical results from the fact that the S1 carbonyl has its radical electrons in opposite spins. When a radical electron adds to a full orbital (in this case the full ? molecular orbital on the alkene 1), it will only couple with the electron with opposite spin. The remaining displaced uncoupled electron is thus the same spin as the radical electron that initially added. Hence, the two radical electrons of the diradical formed immediately upon the singlet addition to the alkene 1 will be of opposite spin. Electrons must be of opposite spin to form a molecular bond, and thus the radical electrons in this diradical from the S1 will quickly bond, closing the molecule to form the oxetane ring 4 (see Sch eme 1).6 However, oxetane ring closure takes longer if the T1 carbonyl adds to the alkene 1. Because the radical electrons in the triplet state carbonyl are of similar spin, the resulting 1,4-diradical 2 will also contain two radical electrons of the same spin. As these radical electrons cannot form a bond due to their identical spin, a relatively longer time must pass before one of the electrons changes spin and the bond forms (see Scheme 1).2 Mechanistic Issues in Synthesis Regioselectivity Because an alkene component, by definition, is composed of two carbon atoms held together by a double bond, there exists two points on the alkene where the excited electron on the carbonyl group may add. In the examples in the figures given previously, the alkene used, 2,3-dimethyl-2-butene, is completely achiral. The two alkene carbons are identical and thus it makes no functional difference to which carbon atom the oxygen adds. However, not all alkene molecules have identical carbons. In fact, most alkenes are chiral and the carbon atoms are not identical. Furthermore, many molecules have two or more carbon-carbon double bonds. The regioselectivity, or the preference of one atom to bond to another, is a major concern in synthesis.7 The regioselectivity concern generally arises when the carbonyl adds to the alkene in the triplet state. If the molecule is going to have a measurable 1,4-diradical configuration, as it does when the T1 carbonyl adds, the excited electron on the oxygen atom will tend to add to the side of the alkene that forms the most stable diradical. Bach1 and Adam7 have done extensive studies on the regioselectivity of the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction. Adam and Stegmann placed various substrates on a chiral alkene and reacted it with benzophenone. Table 1 displays the scheme of the reaction and his results. As can be observed in each reaction, the methyl groups on the original alkene stabilized the diradical so that the majority of the time the oxygen originally added into the carbon with the R1 and X group. However, in general, as the R1 and X substrates increased in size, decreasing the stability differences between the 1,4-diradicals leading to the 3 and 3’ products, the regiosel ectivity also dropped sharply (refer to Table 1). This experiment provides excellent evidence that regioselectivity is determined by the most stable 1,4-diradical.7 The stability of the 1,4-diradical is not the sole determinant of regioselectivity, however. The phenomenon of hydrogen bonding also has proven to influence regioselectivity. The oxygen atom on the carbonyl may be attracted to a specific hydrogen atom on one side of the alkene. This attraction will then cause a hydrogen bond to form. The carbonyl oxygen will then prefer to add to the carbon atom closest to the bond-forming hydrogen atom. Even though entry 1 in Table 1 has a larger X substrate (OH) attached to the alkene carbon than does entry 2 (H), it gives a much higher regioselectivity. This observation can be explained by the fact that the carbonyl oxygen tends to form a hydrogen bond with the hydrogen atom of the hydroxy group. Hydrogen bond effects are seen again in Table 2. Note that entry 5 is the only entry without a hydroxy group and hence has the lowest regioselectivity (refer to Table 2). The reaction of substrates 4e-4h can be seen in Figure 2. The carbonyl oxygen coordi nates with the hydroxy group in each case to form a hydrogen bond (see Figure 2).7 Stereoselectivity In the reaction of acetone with 2,3-dimethyl-2-butene (Figure 1), the reactant molecules were achiral and no new stereocenters were formed. However, in most Paternà ²Ã¢â‚¬â€œBà ¼chi reactions, there are two potentially new stereocenters formed. There could be, of course, feasibly only one stereocenter, or even three, but throughout most of the literature regarding Paternà ²Ã¢â‚¬â€œBà ¼chi reactions, the chemists are centrally concerned with diastereoselectivity.1 Diastereoselective studies involve the preference of a reaction to produce new molecules with two stereocenters. The selective formation of these stereocenters remains a major aim in synthesis. Therefore, the stereochemical information in this review will tend to focus on the recent discoveries in the diastereoselectivity of the Paternà ²Ã¢â‚¬â€œBà ¼chi process. Just as in regiochemistry, the state (T1 or S1) of the excited carbonyl affects the diastereoselectivity of the reaction. Griesbeck and associates2 have researched the dependence of the diastereoselectivity on the electron spin direction. This research specifically concerned the addition of aliphatic aldehydes to 2,3 dihydrofuran and 2,3 dihydropyran. The aldehyde was used as the carbonyl group; it was irradiated to excite the electrons initially into the singlet state. Because the aldehyde only has a lifetime of 1–2 nanoseconds in its excited singlet state, trapping reagents had to be used to intercept the carbonyl group in the S1. The products of an excited state singlet carbonyl could then be studied. Griesbeck found that increased concentration of trapping reagent gave increasingly lower diastereoselectivity as more of the aldehyde was trapped in its singlet state. This lower selectivity can be explained plainly in terms of the transition state of the reaction. As the transition state between the reactant singlet carbonyl and the product oxetane has a negligible lifetime, there is no need to be concerned about intermediate stability, geometrical restrictions, or steric interactions. Thus, there is no need for the singlet to be selective in its direction of addition.2 However, addition selectivity plays an important role in the T1. When the carbonyl in the triplet state adds to the alkene, it forms a 1,4 diradical that has a relatively measurable lifetime. This diradical must undergo intersystem crossing in order to close into the oxetane, which requires rigorous geometrical restrictions. Thus, the geometric configuration and stability of this diradical affects the diastereochemical makeup of the product oxetane. In this particular experiment, Griesbeck et al. found that the reaction through the triplet pathway yielded diastereoselectivities of up to 90:10.2 Because the geometric restrictions of the intermediate diradical in the triplet pathway is a major factor in determining the stereoselectivity of the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction, steric interactions must be considered. Adam and Stegmann7 studied the diastereoselectivity of the addition of aromatic aldehydes to allylic alcohols. Increasing the size of the R group on the alcohol gave increasingly higher diastereoselectivities (refer to Table 2). This observation indicates that the R group is a steric hindrance to the formation of the erythro-product (see Figure 2). Additional studies by Abe et al.8 conclude similarly that increased size of substrate groups will increase the stereoselectivity of the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction. Hydrogen bonding can also affect the stereoselectivity of the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction just as this bonding phenomenon has been shown to affect regioselectivity. In another experiment, Griesbeck and Bondock9 tested the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction of prenol and prenyl acetate. Although there was not a major difference in stereoselectivity attained by replacing the hydroxy group with an acetate group, the hydrogen bonding delayed the intersystem crossing. Hydrogen bonding actually proved to activate the electron further on the carbonyl, causing an increase in the time the carbonyl could remain in its singlet-excited state. This increased lifetime allowed more singlet carbonyls to add to the alkene. Because singlet carbonyls generally add to alkenes irrespective of geometry or orientation, an actual decrease in stereoselectivity was observed due to hydrogen-bonding effects. On the other hand, Bach et al.10 found that in their study, hydrogen bonding increased diastereoselectivity. In this experiment, a very complex molecule was used as the alkene, 3,4-dihydro-1H-pyridin-2-one. Because the carbonyl, a chiral aromatic aldehyde, formed a hydrogen bond with the amide hydrogen on the alkene, it formed a stable exciplex with the alkene. This stabilization allowed the carbonyl to add specifically in a constant geometrical conformation, yielding high diastereoselectivity. Because the geometrical conformation of a molecule is often altered by increased heat, temperature can also play a major role in stereoselectivity. Adam and associates11 studied the Paternà ²Ã¢â‚¬â€œBà ¼chi addition of benzophenone to both cis- and trans-cyclooctene at a temperature range of –95  °C to 110  °C. Except for the two extremes, temperature intervals of 20  °C were used. It was found that increasing the temperature increased the likelihood of the conformation change of the cyclooctene. If the cyclooctene changed conformation, the oxetane product was also changed. Lower temperatures favored the highest diastereoselectivity in each case. Specific Synthetic Applications Ring Opening Reactions Once an oxetane ring is formed, it can be then opened conventionally with an agent such as LiAlH4 or sodium metal, creating an alcohol. The Paternà ²Ã¢â‚¬â€œBà ¼chi reaction thus becomes an intermediate reaction rather than a terminal one. The advantage of using the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction as an intermediate in synthesis concerns stereoselective purity. The ring is opened in a way that the reaction takes place at a non-stereogenic center, and the stereoselectivity is thus preserved.12 Ring opening reactions are key in synthesizing many natural products. For example, prostaglandin analogues and ephedrine are products used often in medicine, and these can be synthesized utilizing the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction and then opening the oxetane ring. Insect pheromones and asteltoxin, a potent inhibitor of ATP synthesis, can also be formed using this ring-opening process as an intermediate.1 Bach and his group specifically completed the total synthesis of (+)-Preussin.13 (+)-Preussin is a useful antifungal agent. However, only the (+)-enantiomer is active. Therefore, it is absolutely imperative that the stereoselectivity is pure. This purity can be preserved through the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction. The final product can be formed beginning with the commercially available (S)-pyroglutaminol. The total synthesis of (+) Preussin is given in Scheme 2. (+)-Preussin is certainly useful, but it is in no way the limit of the ring-opening process. As mentioned above, ring-opening reactions can be used to create diastereomerically pure alcohols. The final structure of the alcohol is based on the structure of the oxetane ring molecule. Bach and Eilers12 worked on the synthesis of diols. In this experiment, an oxetane was prepared with a protecting group. The protecting group, a trimethylsilyl ether, and the oxygen atom of the oxetane ring were attached to adjacent carbons. After removing the protecting group, LiAlH4 was applied to the oxetane, opening the ring. A trans-1,2-diol was then obtained at 69-99% yield. Still, diols are not the only alcohols that can be obtained from oxetane rings. Adding N-Acyl enamines to aldehydes in the presence of light energy causes the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction. Subsequent ring opening using LiAlH4 or LiSBn then can form a cis 1,2 amino alcohol. Bach and Schrà ¶der15 studied this particular synthesis and were able to obtain these products in 65-86% yields. Formation of Natural Oxetane Products Although the ring opening process is extremely useful in synthesis, it is not always necessary to continue after the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction has taken place. Some useful natural compounds contain oxetane components and thus use the Paternà ²Ã¢â‚¬â€œBà ¼chi process as a terminal step. Oxetanocin, an anti-cancer drug, was synthesized using this reaction. Additionally, the ?-amino acid (?)-oxetin was produced by adding an N-acyl enamine to an aldehyde. (?)-Oxetin has proven to act usefully as an antibiotic and herbicide.4 Summary Understanding the basics of the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction is straightforward, but the scope of its application and its impact on photochemistry is extensive. Although the majority of chemists do not deal with photochemical processes, knowledge of at least the existence of the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction can facilitate the solution to many synthetic problems. The simultaneous formation of both a carbon-oxygen bond and a carbon carbon bond is extremely useful in connecting molecules together. Furthermore, the universal concern of regio- and stereochemical yields are usually solved using the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction, which generally adds both regioselectively and stereoselectively. One can generally predict the regio- and stereoselectivity by an analysis of the chemical structure of the two reactants. There are several factors influencing the selectivity, which include diradical stability, steric interaction, hydrogen bonding, and temperature. Additionally, understanding the mechanistic nature of the singlet- and triplet-excited states of the carbonyl plays an important role in predicting and preparing yields. Further knowledge of the mechanism of the reaction will allow for much more accurate and efficient synthesis. Improved synthetic methods will lead to additional discoveries and more effective manufacture of important organic compounds. (?)-Oxetin and oxetanocin are two oxetane-containing compounds that can be synthesized using the Paternà ²Ã¢â‚¬â€œBà ¼chi reaction. However, not all useful compounds created with this reaction are oxetanes. (+)-Preussin, ephedrine, and prostaglandin analogues are alcohols that are synthesized using ring-opening reactions following the Paternà ²Ã¢â‚¬â€œBà ¼chi process. As chemists at both universities and in the pharmaceutical laboratories gain more knowledge of efficient synthetic techniques, important natural compounds can be more effectively and cheaply made available to their target audience. The Paternà ²Ã¢â‚¬â€œBà ¼chi reaction has proven useful and effective in the past and as it continues to be studied, it will only enhance the growing arsenal of synthetic chemists. Literature Cited 1. Bach, T. Stereoselective Intermolecular [2+2]-Photocycloaddition Reactions and Their Application in Synthesis. Synthesis 1998, 5, 683–703. 2. Griesbeck, A. G.; Fiege, M.; Bondock, S.; Gudipati, M. S. Spin Directed Stereoselectivity of Carbonyl–Alkene Photocycloadditions. Organic Lett. 2000, 2, 3623–3625. 3. Bach, T.; Bergmann, H.; Brummerhop, H.; Lewis, W.; Harms, K. The [2 + 2]-Photocycloaddition of Aromatic Aldehydes and Ketones to 3,4-Dihydro-2-pyridones: Regioselectivity, Diastereoselectivity, and Reductive Ring Opening of the Product Oxetanes. Chem. Eur. J. 2001, 7, 4512–4521. 4. Bach, T.; Schrà ¶der, J. A Short Synthesis of (?)-Oxetin. Liebigs Ann. / Rescueil 1997, 2265–2267. 5. Bach, T. The Paternà ²Ã¢â‚¬â€œBà ¼chi Reaction of N-Acyl Enamines and Aldehydes – The Development of a New Synthetic Method and its Application to Total Synthesis and Molecular Recognition Studies. Synlett 2000, 12, 1699–1707. 6. Kuteladze, A.G. Conformational Analysis of Singlet–Triplet State Mixing in Paternà ²Ã¢â‚¬â€œBà ¼chi Diradicals. J. Am. Chem. Soc. 2001, 123, 9279–9282. 7. Adam, W.; Stegmann, V. R. Hydroxy-Group Directivity in the Regioselective and Diastereoselective [2+2] Photocycloaddition (Paternà ²Ã¢â‚¬â€œBà ¼chi Reaction) of Aromatic Carbonyl Compounds to Chiral and Achiral Allylic Substrates: The Preparation of Oxetanes with up to Three Stereogenic Centers as Synthetic Building Blocks. Synthesis 2001, 8, 1203–1214. 8. Abe, M.; Torii, E.; Nojima, M. Paternà ²Ã¢â‚¬â€œBà ¼chi Photocyclization of 2-Siloxyfurans and Carbonyl Compounds. Notable Substituent and Carbonyl (Aldehyde vs. Ketone and Singlet- vs. Triplet-Excited State) Effects on the Regioselectivity (Double-Bond Selection) in the Formation of Bicyclic exo-Oxetanes. J. Org. Chem. 2000, 65, 3426–3431. 9. Griesbeck, A.G.; Bondock, S. Paternà ²Ã¢â‚¬â€œBà ¼chi Reactions of Allylic Alcohols and Acetates with Aldehydes: Hydrogen-Bond Interaction in the Excited Singlet and Triplet States? J. Am. Chem. Soc. 2001, 123, 6191–6192. 10. Bach, T.; Bergmann, H.; Harms, K. High Facial Diastereoselectivity in the Photocycloaddition of a Chiral Aromatic Aldehyde and an Enamide Induced by Intermolecular Hydrogen Bonding. J. Am. Chem. Soc. 1999, 121, 10650–10651. 11. Adam, W.; Stegmann, V. R.; Weinkà ¶tz, S. Unusual Temperature-Dependent Diastereoselectivity in the [2+2] Photocycloaddition (Paternà ²Ã¢â‚¬â€œBà ¼chi Reaction) of Benzophenone to cis- and trans-Cyclooctene through Conformational Control. J. Am. Chem. Soc. 2001, 123, 2452–2453. 12. Bach, T.; Eilers, F. Diastereomerically Pure 1,2-Diols by Nucleophilic Displacement Reactions of 3-Oxetanols – A Study Directed Towards the Identification of Suitable Nucleophiles and the Elucidation of Possible Side Reactions. Eur. J. Org. Chem. 1998, 2161–2169. 13. Bach, T.; Brummerhop, H. Unprecedented Facial Diastereoselectivity in the Paternà ²Ã¢â‚¬â€œBà ¼chi Reaction of a Chiral Dihydropyrole- A Short Total Synthesis of (+)-Preussin. Angew. Chem. Int. Ed. 1998, 37, 3400–3401. 14. Bach, T.; Brummerhop, H.; Harms, K. The Synthesis of (+)-Preussin and Related Pyrrolidinols by Diastereoselective Paternà ²Ã¢â‚¬â€œBà ¼chi Reactions of Chiral 2 Substituted 2,3-Dihydropyrroles. Chem. Eur. J. 2000, 6, 3838–3843. 15. Bach, T.; Schrà ¶der, J. Photocycloaddition of N-Acyl Enamines to Aldehydes and Its Application to the Synthesis of Diastereomerically Pure 1,2-Amino Alcohols. J. Org. Chem. 1999, 64, 1265–1273. Research Papers on The Mechanism of the Paterno-Buchi Reaction and its Application in the Organic Synthesis ReviewOpen Architechture a white paperEffects of Television Violence on ChildrenMoral and Ethical Issues in Hiring New EmployeesGenetic EngineeringRiordan Manufacturing Production PlanBionic Assembly System: A New Concept of SelfThe Project Managment Office SystemAssess the importance of Nationalism 1815-1850 EuropeDefinition of Export QuotasMarketing of Lifeboy Soap A Unilever Product

How to Write a Thesis

How to Write a Thesis How to Write a Thesis How to Write a Thesis By Mark Nichol An analytical or persuasive essay is a capsule thesis, and, like its more substantial analogue, it requires a thesis statement. Here are some notes about how to develop that statement. A thesis statement is a sentence (or two) that encapsulates and introduces an analysis or argument. An essay benefits from a thesis statement by concisely expressing the writer’s argument and serving as a basis for developing and organizing it. If you are assigned to write an essay, whether in an academic or professional setting, the topic may or may not be given. If the topic is specified, you can produce the thesis statement by converting the explanation of the assignment into a question; your response to that question is the thesis statement. For example, if you are asked to write about feeding wild animals, you might pose the question â€Å"Why is feeding wild animals a bad idea?† You might reply, â€Å"Feeding wild animals disrupts natural habits in animals and endangers them and the people who feed them.† You would then research the issue and jot down notes about how feeding wild animals, or making food available to them, might make them dependent on food supplied by humans, which in turn may affect their ability to forage or hunt when the human-provided food may no longer be available. Another supporting point would be the consequences to humans: Animals that are fed may become insistent or even aggressive, damaging property or attacking humans or their pets; diseased animals may infect humans they come in contact with, and so on. If it is your responsibility to select the topic, consider these elements of a successful persuasive essay: the topic is an issue that is arguable (that is, it isn’t a given that every reader would agree with you), and it can be adequately discussed in the framework of the assignment. In addition, confirm that you are adhering to one main idea and that, when you are done, you have not only stated your views but also supported your conclusions. Distinguishing characteristics of effective theses are that they are specific, they clearly state the writer’s position, and they encourage discussion. These qualities should be apparent in the work as a whole as well as in the thesis statement itself. Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Business Writing category, check our popular posts, or choose a related post below:50 Idioms About Legs, Feet, and Toes30 Baseball IdiomsThe Uses of â€Å"The†