Dehydrogenative Meyer-Schuster-like rearrangement: A gold-catalyzed reaction generating an alkyne

Abstract

Easily accessible propargylic esters are converted to the inverted alkynyl ketones in an oxidative gold-catalyzed reaction. Gagosz's catalyst in combination with PhI(OAc)2 is the best system for this conversion and 18 examples with yields up to 80 % are reported. The results indicate that the triple bond in the product is formed by elimination from a vinylgold intermediate. In a formal sense the new conversion overall is a dehydrogenative Meyer-Schuster rearrangement. It takes alkynes: Propargyl esters can be converted into alkynyl ketones by a new oxidative gold-catalyzed reaction. The best catalyst system is Ph3PAuCl/AgNTf2 in combination with the oxidant PhI(OAc)2. The yields are as high as 80 % and the reaction can be conducted in the presence of air. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.