A New Mode of Cyclization of Enynes: Synthesis of Cycloalkyl Ketones through a Platinum‐Catalyzed Hydrative Cycloisomerization Reaction

Abstract

Abstract A new platinum‐catalyzed cascade reaction that proceeds through an unusual cyclization pathway of enyne derivatives is described. This operationally simple, air‐ and moisture‐tolerant reaction affords cycloalkyl ketone derivatives in a straightforward manner. The reaction can be considered as an unprecedented abnormal platinum‐catalyzed cyclization of enynes. The role of the platinum catalyst promoting at least three different reactions in this auto‐tandem catalytic process should also be remarked. The reaction also includes an unusual site‐selective hydration of a practically symmetrical carbon‐carbon triple bond directed by a hydroxy group. In this work we also describe the first platinum‐catalyzed intramolecular hydroalkylation of an unactivated olefin with a simple dialkyl ketone.