Studies on the structure-enantioselectivity relationships in the catalytic asymmetric intramolecular cyclopropanation reaction of alpha-diazo-beta-keto sulfones possessing a methyl-substituted phenyl group

摘要

This manuscript describes studies on structure-enantioselectivity relationships in the catalytic asymmetric intramolecular cyclopropanation (IMCP) reaction of alpha-diazo-beta-keto sulfones possessing a methyl-substituted phenyl group. Enantioselectivity of the IMCP reaction of the alpha-diazo-beta-keto sulfones was varied by the position of a methyl group on the pheny] group in the substrate, and the 2,3-dimethylphenyl sulfone 11h provided the product 12h in 95% yield with 93% ee. This yield is superior to that of the substrate with a mesityl sulfone 11b, and the product 12h is useful because alkylation of its cyclopropane-opened P-keto sulfone derivative 15h provides the C-alkylated product as a major product. (c) 2006 Elsevier Ltd. All rights reserved.