Gold-Catalyzed Sequential Activation of Propargylic Carboxylates: A Facile Route to Benzoannulenes

Abstract

A cascade reaction of 1-(2-(3-acetoxyprop-1-ynyl)phenyl)prop-2-ynyl acetate and its derivatives is catalyzed by gold to give the corresponding benzo[7]annulenes (see scheme) in excellent yields. A double activation of the gold catalyst toward two different propargylic carboxylates was proposed. Benzoannulenes were hydrolyzed to 8-hydroxybenzo[7]annulene-5-ones.