Semihydrogenation of alkynes in the presence of Ni(0) catalyst using ammonia-borane and sodium borohydride as hydrogen sources

The selective semihydrogenation of terminal and internal alkynes was achieved using complexes of the type [(P-P)Ni(η2-C,C-alkyne)] (P-P = chelating diphospine ligands), which behave as the active catalysts and were generated in situ. Boron-hydride derivatives such as ammonia-borane (AB) or sodium boron hydride (SBH) were used as hydrogen sources. In the case of internal alkynes, the stereoselective formation of cis- or trans-alkenes was achieved in high yields and under mild reaction conditions.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (84 K)Download as PowerPoint slideResearch highlights▶ The selective semihydrogenation of terminal and internal alkynes was achieved. ▶ The use of catalytic amounts of Ni(0) allowed a mild process. ▶ Ammonia-borane (AB) or sodium boron hydride (SBH) was used as hydrogen source. ▶ The stereoselective formation of cis or trans-alkenes was achieved in high yields.