Chiral alpha-substituted carbonyls and alcohols from the S(N)2 ' displacement of cuprates on chiral carbonates: An alternative to the alkylation of chiral enolates

A highly stereoselective sequence of reactions, based on the anti-selective S(N)2' addition of cuprates to allylic carbonates, transforms alkynes or a lkenyl halides into carbonyls having cr-chiral centers. The method, which u ses menthone as a chiral auxiliary, is a useful alternative to the. alkylat ion of chiral enolates with the added advantage of allowing for the "alkyla tion" of sec- and tert-alkyl and aryl groups.