A novel copper-catalyzed selective semihydrogenation of terminal alkynes using hypophosphorous acid as hydrogen donor took place efficiently to afford the corresponding alkenes in high yields. A broad range of substituted terminal aromatic and aliphatic alkenes, including terminal dienes and enynes bearing internal triple bonds, can be efficiently synthesized by this reaction.

Acid. -The optimized conditions allow the selective semihydrogenation of a broad range of terminal aromatic and aliphatic alkynes to afford the corresponding alkenes in high yields. -(CAO, H.; CHEN, T.; ZHOU*, Y.; HAN, D.; YIN, S.-F.; HAN, L.-B.; Adv. Synth. Catal. 356 (2014) 4, 765-769, http://dx.