Asymmetric alkylation mediated by tricyclic chiral sultam auxiliaries

Article abstract of DOI:10.1016/S0040-4020(99)00872-8

The use of enantiomerically pure sultams (+)-1 and (-)-1 as practical chiral auxiliaries for asymmetric alkylation reactions is described in full. Deprotonation of the N-acylated products derived from the auxiliaries with sodium hexamethyldisilazide followed by treatment with alkyl halides gave products with high diastereoselectivity. On treatment with excess racemic α- bromopropanoate or α-bromobutanoate, the enolates of the corresponding N- acyl sultam underwent highly diastereoselective alkylations to afford products with a complete absolute control of two contiguous chiral centres.