CHIRAL OXIMES IN ASYMMETRIC-SYNTHESIS .2. ADDITION OF BUTYLLITHIUM TOBENZALDEHYDE O-(1-PHENYLALKYL)OXIMES

A series of benzaldoxime ethers PhCH=NOCHRPh 5 bearing a chiral auxili ary on oxygen have been prepared to investigate the effect of the auxi liary on the diastereoselectivity of the addition of butyllithium to t he oxime C=N bond, By increasing the size of the alkyl group R in the auxiliary, OCHRPh, an increase in de is observed, with the best compro mise between ready availability and high levels of asymmetric inductio n in the product 6 being achieved with the oximes derived from O-(1-ph enylbutyl)hydroxylamine.