Copper- and Borinic Acid-catalyzed Propargylic Etherification of Propargylic Carbonates with Benzyl Alcohols

Abstract

Propargylic substitution reactions have offered useful synthetic methods because further transformations based on the alkyne moiety in the propargylic substituted products was readily achieved to construct more complex organic compounds. A large number of works have been devoted to enantioselective propargylic substitution reactions with a variety of nucleophiles. However, successful examples of the use of alcohols as nucleophiles have been quite limited until now. To achieve utilization of aliphatic alcohols, herein we report the use of combined catalysis of a copper-pybox complex and a borinic acid. In this catalytic system, aliphatic alcohols such as benzyl alcohol derivatives were successfully applied to afford the corresponding propargylic etherified products in good yields with high enantioselectivities.