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The Cope elimination is very similar to the Hofmann elimination in principle, but occurs under milder conditions. It also favors the formation of the Hofmann product, and for the same reasons. [3] An example of a Hofmann elimination (not involving a contrast between a Zaitsev product and a Hofmann product) is the synthesis of trans-cyclooctene. [4]
In organic chemistry, the E i mechanism (Elimination Internal/Intramolecular), also known as a thermal syn elimination or a pericyclic syn elimination, is a special type of elimination reaction in which two vicinal (adjacent) substituents on an alkane framework leave simultaneously via a cyclic transition state to form an alkene in a syn elimination. [1]
These intramolecular interactions are relevant to the distribution of products in the Hofmann elimination reaction, which converts amines to alkenes. In the Hofmann elimination, treatment of a quaternary ammonium iodide salt with silver oxide produces hydroxide ions, which act as a base and eliminate the tertiary amine to give an alkene. [11]
Vinylacetylene was first synthesized by Hofmann elimination of the related quaternary ammonium salt: [4] [(CH 3) 3 NCH 2 CH=CHCH 2 N(CH 3) 3]I 2 → 2 [(CH 3) 3 NH]I + HC≡C-CH=CH 2. It is usually synthesized by dehydrohalogenation of 1,3-dichloro-2-butene. [5] It also arises via the dimerization of acetylene, which is catalyzed by copper(I ...
All elimination reactions involve the removal of two substituents from a pair of atoms in a compound. Alkene, alkynes, or similar heteroatom variations (such as carbonyl and cyano) will form. The E1cB mechanism is just one of three types of elimination reaction. The other two elimination reactions are E1 and E2 reactions.
The oxime group is hydrogenated to the amine 11 with platinum in acetic acid and alkylation with iodomethane gives the quaternary ammonium salt 12 and subsequently the betaine 13 after reaction with silver oxide. Quinine's vinyl group is then constructed by Hofmann elimination with sodium hydroxide in water at 140 °C.
At –75 °C, the product ratio is 48:35:17 mixture of n-hexane, 2-methylpentane, and 3-methylpentane. The ratio is remarkably close to the statistical product ratio of 6:4:2 (~50:33:17) based on the number of available C–H bonds at each position that could undergo methylene insertion. As a result, Doering and coworkers concluded:
Elimination reaction of cyclohexanol to cyclohexene with sulfuric acid and heat [1] An elimination reaction is a type of organic reaction in which two substituents are removed from a molecule in either a one- or two-step mechanism. [2] The one-step mechanism is known as the E2 reaction, and the two-step mechanism is known as the E1 reaction ...