Enantioselective indium(<scp>i</scp>)-catalyzed [4 + 2] annulation of alkoxyallenes and β,γ-unsaturated α-keto esters

Abstract

An indium(<sc>i</sc>)–chiral phosphoric acid complex was found to catalyze the enantioselective [4 + 2] annulation reaction of β,γ-unsaturated α-keto esters with alkoxyallenes, affording cyclic <italic>O</italic>,<italic>O</italic>-acetals in good yields and with high regio- and stereo-selectivities.