Highly Enantioselective Reactions of alpha-Sulfonyl Carbanions of Trifluoromethyl Sulfones

摘要

The formation of carbon-carbon bonds by using readily generated alpha-sulfonyl carbanions and their applications to the synthesis of natural products have been extensively studied. Sulfones having chir-ality at the a position are known to show biological activity, for example, dorzolamide has antiglaucoma activity, but little attention has been paid to the enantioselective reaction of alpha-sulfonyl carbanions, probably because of the difficulty in obtaining high enantioselectivity. However, there are a few precedents: the enantioselective reaction of alpha-lithio sulfones derived from an allyl sulfone using a chiral amino alcohol as a chiral ligand and by using chiral lithium amides. However, the enantioselectivities reported in these reports are unsatisfactory. Herein we report the first highly and catalytic enantioselective reaction of alpha-lithiated sulfones.