Gold-catalyzed ring expansions of 1-alkynylcyclobutanol derivatives via tandem hydration and alpha-ketol rearrangement

Abstract

We report herein the gold-catalyzed tandem hydration/alpha-ketol rearrangement of 1-alkynylcyclobutanol derivatives, leading to cyclopentanones bearing an alpha-hydroxy substituted quaternary center. In the presence of water, coordination of gold catalyst onto alkynyl moiety triggers hydration rather than a direct ring expansion, which followed by unprecedented Au-catalyzed alpha-ketol rearrangement. The details and the scope of this method are presented.