Palladium-Catalyzed Semihydrogenation of Alkynes with EtOH: Highly Stereoselective Synthesis of E- and Z-Alkenes

Abstract

AbstractA palladium-catalyzed semihydrogenation of alkynes to E- and Z-alkenes employing EtOH as the hydrogenating agent is reported. The selectivity of the reaction system was effectively controlled by ­ligand/additive and solvent regulation. The use of sodium acetate/­triethanolamine (NaOAc/TEOA), THF, and (1R,2R)-bis[(2-­methoxyphenyl)phenylphosphino]ethane [(R,R)-DIPAMP] in CH3CN was critical for the stereoselective semihydrogenation of alkynes. The general applicability of this procedure was highlighted by the synthesis of more than 36 alkenes, in good yields with high stereoselectivities.