Intramolecular palladium-catalyzed alkene carboalkynylation

Carbocycles are essential building blocks for the synthesis of natural and synthetic bioactive compounds. Herein, we report the first example of palladium-catalyzed intramolecular carboalkynylation of non-activated olefins. Using activated carbonyl compounds as nucleophiles and an alkynyl bromide as an electrophile, the reaction gives access to cyclopentanes in 44-93% yield and one example of cyclohexane in 31% yield with simultaneous formation of a SP3-SP C-C bond. The reaction therefore combines ring formation with the introduction of a versatile triple bond for further functionalization. (C) 2015 Elsevier Ltd. All rights reserved.