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Azomethine ylides are nitrogen-based 1,3-dipoles, consisting of an iminium ion next to a carbanion. They are used in 1,3-dipolar cycloaddition reactions to form five-membered heterocycles, including pyrrolidines and pyrrolines.
28 de feb. de 2022 · A ylide is a neutral species in which there is a carbon atom bearing a formal charge of -1 bound to a heteroatom bearing a formal charge of +1. Ylides are classified based on the nature of the positively charged heteroatom.
6 de feb. de 2018 · The two components of this reaction are: a carbonyl compound (aldehydes and ketones both work, but not esters or amides) a rather strange-looking species known as an ylide. (specifically, a “phosphonium ylide”, because there are also ylides of nitrogen and sulfur).
27 de ene. de 2010 · New reactions of azomethine ylides with nontraditional dipolarophiles are reported. Azomethine ylides, formed in situ via decarboxylative condensations of α-amino acids with aldehydes, undergo reactions with naphthols, indoles, alkynes, and nitroalkanes.
23 de ene. de 2023 · Ylides are specific examples of zwitterions, which are molecules that contain positive and negative charges. The most common example of a zwitterion is probably an amino acid, which contains a positive ammonium ion and a negative carboxylate ion, within the same molecule.
The Wittig Reaction allows the preparation of an alkene by the reaction of an aldehyde or ketone with the ylide generated from a phosphonium salt. The geometry of the resulting alkene depends on the reactivity of the ylide.
Azomethine ylides are a special class of carbonyl ylides formed by carbene association with the carbonyl oxygen of an amide. From: Comprehensive Organometallic Chemistry II , 1995 Add to Mendeley
