Stereochemistry in the Knoevenagel reaction of methyl arylsulphinylacetate and aldehydes

Autor:	Tadashi Tamura, Aritsune Kaji, Rikuhei Tanikaga, Naoto Konya
Rok vydání:	1987
Předmět:	Steric effects chemistry.chemical_classification chemistry Stereochemistry Yield (chemistry) Carboxylic acid Stereoselectivity Knoevenagel condensation Aliphatic compound Aldehyde Carbanion
Zdroj:	Journal of the Chemical Society, Perkin Transactions 1. :825
ISSN:	1364-5463 0300-922X
DOI:	10.1039/p19870000825
Popis:	The stereochemistry of the mechanism of the amine-catalyzed Knoevenagel reaction has been studied. Simple treatment of methyl arylsulphinylacetate (1) and aldehydes (2) with a catalytic amount of a secondary amine produced thermodynamically stable E-alkenes (E)-(3), and the intermediary diastereoisomeric amino compounds (8) were isolated. In acetic acid (8) underwent anti-elimination to yield (E)-(3) and (Z)-(3), while under the Knoevenagel reaction conditions only compounds (E)-(3) were obtained from (8). Both condensation and elimination were found to be reversible, and the stereochemistry of products was determined in the elimination step via stable planar carbanions (9), in which the small difference in the steric requirements of sulphinyl and carbonyl group is effective for the formation of (E)-(3).
Databáze:	OpenAIRE
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