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

作者：Di Bari Lorenzo^*; Guillarme Stephane; Hanan John; Henderson Andrew P; Howard Judith A K; Pescitelli Gennaro; Probert Michael R; Salvadori Piero; Whiting Andrew

来源：European Journal of Organic Chemistry, 2007, (34): 5771-5779.

DOI：10.1002/ejoc.200700731

• cycloaddition
• asymmetric catalysis
• configuration analysis
• nitrogen heterocycle
• Lewis acid
• reaction mechanism

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.

• 出版日期2007-12