Palladium–dppb–borate‐catalyzed regioselective synthesis of cinnamate esters by alkoxycarbonylation of phenylacetylene

The regioselective alkoxycarbonylation of phenylacetylene into various cinnamate esters was achieved with a catalyst system formed from palladium (II), 1,4‐bis(diphenylphosphino) butane (dppb) and salicylborate complex in acetonitrile as a solvent. The influence of various parameters on the overall conversion of phenylacetylene and the selectivity of the reaction were studied systematically by varying the type of palladium complex, acids promoter, CO pressure, temperature and the reaction time. This investigation allowed us to obtain the predominant formation of cinnamate esters with excellent selectivity (90–96%). Copyright © 2008 John Wiley & Sons, Ltd.