Premium
Application of Zinc(II)–Binol for the Formal Aza‐Diels–Alder Reaction of N ‐Arylimines with Danishefsky's Diene: CD‐Based Absolute Stereochemistry Determination, Origin of Asymmetric Induction and Mechanistic Considerations
Author(s) -
Di Bari Lorenzo,
Guillarme Stéphane,
Hanan John,
Henderson Andrew P.,
Howard Judith A. K.,
Pescitelli Gennaro,
Probert Michael R.,
Salvadori Piero,
Whiting Andrew
Publication year - 2007
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200700731
Subject(s) - chemistry , asymmetric induction , zinc , diene , denticity , lewis acids and bases , catalysis , imine , stereochemistry , acetal , enantiomer , medicinal chemistry , chiral lewis acid , enantioselective synthesis , organic chemistry , crystal structure , natural rubber
Abstract Zinc(II)–binol has been employed as an efficient Lewis acid catalyst (10 or 100 mol‐% loading) for the formal aza‐Diels–Alder reaction of ester, furyl and dimethyl acetal‐substituted N ‐aryl imines. Asymmetric induction varies from poor to good, with the major enantiomer obtained being ( S ) when the ( S )‐binol complex has been employed. The absolute stereochemistry of the dimethyl acetal‐substituted cycloaduct was determined by CD, and both efficient aza‐Diels–Alder reaction and asymmetric induction are proposed to be dependent upon the formation of bidentate zinc‐imine complexes. These complexes have been modelled using semi‐empirical methods. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)