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Corey–Winter Olefin Synthesis
The Corey–Winter olefin synthesis (also known as Corey–Winter–Eastwood olefination) is a series of chemical reactions for converting 1,2-diols into olefins. It is named for the American chemist and Nobelist Elias James Corey and the American-Estonian chemist Roland Arthur Edwin Winter. Often, thiocarbonyldiimidazole is used instead of thiophosgene as shown above, since thiophosgene has a similar toxicity profile as phosgene, whereas thiocarbonyldiimidazole is a much safer alternative. Mechanism The reaction mechanism involves the formation of a cyclic thiocarbonate from the diol and thiophosgene. The second step involves treatment with trimethyl phosphite, which attacks the sulfur atom, producing S=P(OMe)3 (driven by the formation of a strong P=S double bond) and leaving a carbene.Horton, D.; Tindall, Jr., C. G. ''J. Org. Chem.'' 1970, ''35(10)'', 3558-3559. () This carbene collapses with loss of carbon dioxide to give the olefin. An alternative mechanism does not involv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Reaction
A chemical reaction is a process that leads to the chemistry, chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an Gibbs free energy, energy change as new products are generated. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the Atomic nucleus, nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive Chemical element, elements where both electronic and nuclear changes can occur. The substance (or substances) initially involved in a chemical reaction are called reagent, reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more Product (c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
