Preparation of optically active α-hydroxy oxime ether by diastereoselective imino 1,2-Wittig rearrangement of hydroximates and its application to synthesis of (+)-cytoxazone

The diastereoselective imino 1,2-Wittig rearrangement of hydroximates provides a novel method for the construction of optically active α-hydroxy oxime ethers. Upon treatment with LDA, allyl p-methoxyphenylhydroximate carrying a chiral auxiliary smoothly underwent diastereoselective rearrangement to give the (R)-α-hydroxy oxime ether which was effectively converted into (+)-cytoxazone.