1,2-Nucleophilic additions of organolithium reagents to chiral oxime ethers

Chiral oxime ethers are readily prepared from chiral alkoxyamines derived from ephedrine and norephedrine. These chiral oxime ethers of isobutyraldehyde and benzaldehyde undergo 1,2-nucleophilic addition reactions with alkyllithium reagents (n-BuLi, PhLi and n-BuLi, tert-butyllithium, respectively) to afford the chiral alkoxyamines with a diastereomeric excess of 64-88%. Reduction of the alkoxyamines with LiAlH 4 gave the corresponding chiral amines. The diastereoselectivity of the reaction appears to directly mirror the E:Z ratio of the starting oxime ethers.