HIGHLY DIASTEREOSELECTIVE SYNTHESIS OF SUBSTITUTED EPICHLOROHYDRINS AND REGIOSELECTIVE PREPARATION OF ALLYL ALCOHOLS USING CHLORO OR IODOMETHYLLITHIUM

摘要

Substituted epichlorohydrins 3 or 6 are obtained from alpha-bromo or alpha-chlorocarbonyl compounds (1 or 4) and chloro or iodomethyllithium, respectively. Starting from alpha-bromocarbonyl compounds 1 or acyclic alpha-chloro ketones the reaction takes place with total diastereoselectivity. Treatment of epichlorohydrins 3 or 6 with lithium iodide affords the same substituted allyl alcohols 7 in a regioselective manner. A mechanism to explain this transformation is proposed. Regioisomeric allyl alcohols 11 are prepared by reaction of epichlorohydrins 6 with lithium powder. [References: 50]