Distinct selective alkene hydrosilylation catalyzed by acylenalato cobalt hydrides

Abstract

In this article, the catalytic performance of acylenolato cobalt(III) hydrides [Co^III(O∩CO)(PMe₃)₃H] (O∩CO = acylenolato ligand) 1–3 for alkene hydrosilylation was studied. The experimental results indicate that the three cobalt(III) hydrides exhibit excellent catalytic activity for the hydrosilylation of alkenes. The catalytic effect of hydride 1 is superior to that of complex 2 or 3. This catalytic system has good substrate universality and high selectivity. The catalytic conditions (1 h, 50 °C) are mild. Aromatic alkenes and alkyl alkenes generate respectively Markovnikov products and anti-Markovnikov products with 99% selectivity. In the study of the catalytic mechanism, the silyl cobalt(III) intermediate generated by the reaction between cobalt(III) hydride and silane is considered as the real catalyst. A catalytic mechanism is proposed on the basis of the experimental information and literature reports.