Studies on the stereoselective opening of aryl-epoxides using trialkylaluminium

Abstract

Epoxides are versatile intermediates in organic synthesis because they could undergo stereospecific nucleophilic ring opening to yield bifunctional compounds. We focused on the stereoselective opening reaction of various aryl-epoxides mediated by Trialkylaluminium. We examined solvents, temperature, concentration, addition rates, and equivalent of trialkylaluminium, and also attempted to change electronic or steric environments as factors influencing the selectivity. We found the optimized condition for syn-addition in hexane at room temperature. Extent of electron-donating power of aryl group was important to decide syn-stereoselectivity, and bulkier alkyl substituents gave larger syn-addition products. Hydride or alkyl shifted compounds were obtained when we used bulky alkyl substituent or Trialkylaluminium.