ACID-CATALYZED RING-OPENING REACTIONS OF OPTICALLY PURE 2-ARYL-3,3-DIMETHYLOXETANES

Some ring-opening reactions of optically pure 2-aryl-3,3-dimethyl oxetanes have been examined under strongly protic or Lewis acid conditions, Ring-opening occurred at the benzylic position and partial inversion of configuration was observed in the case of hydrolysis or alcoholysis of the optically pure oxetanes catalyzed by H2SO4. The acid concentration affects the degree of inversion of configuration in water or methanol. On reaction with n-butyllithium or lithium thiolates aided by Lewis acid (BF3.ether) the corresponding beta-substituted benzyl alcohols were obtained. Substitution now occurs at the least hindered carbon and the configuration of the asymmetric center remains unaffected.