Tandem indium(III)-catalyzed cyclization and intermolecular hydrofunctionalization of 1,6-enynes

Abstract

A tandem indium(III)-catalyzed cyclization and intermolecular hydrofunctionalization of 1,6-enynes for the stereoselective synthesis of functionalized carbo- and heterocycles is reported. The synthetic transformation involves a regio- and stereoselective 5-exo-dig 1,6-enyne cyclization followed by intermolecular nucleophilic addition of alcohols (including water), carboxylic acids, arenes and trimethylsilyl azide. Remarkably, the reaction proceeds under mild reaction conditions with low catalyst loading (5 mol%) using unexpensive commercial indium(III) halides in good yields with broad chemoselectivity and high regio- and stereoselectivity,