Copper-catalyzed Direct Oxidative α-Arylation of Pyrrolidine with Phenols and Naphtols

An efficient procedure for the direct arylation of pyrrolidine with phenols and naphtols is reported. Upon reaction with catalytic amounts of a binuclear copper(II)-7-azaindole complex under an atmosphere of oxygen, pyrrolidine is smoothly oxidized to the corresponding imine which can be trapped in situ by a series of phenols and naphtols in fair to good yields. This copper-catalyzed direct oxidative arylation of pyrrolidine offers an efficient entry to alpha-aryl-pyrrolidines in a single step and without the need for protecting or directing groups.