HSiR₃/CO as the Potent Reactant Combination in Developing New Transition-Metal-Catalyzed Reactions

Transition-metal-catalyzed reactions of various organic compounds with HSiR₃ and CO are reviewed. A brief summary of the earlier works using Co₂(CO)₈ as the catalyst is given and an extensive review of recent studies using transition metal catalysts other than Co₂(CO)₈ is described. The Co₂(CO)₈-catalyzed reactions of olefins or oxygen-containing compounds with HSiR₃ and CO can be classified into four categories; formylation, 1,2-bis(siloxy)vinylation, siloxymethylenation, and siloxymethylation depending on the structure of the substrates used as well as reaction conditions employed. Ring-opening silylformylation of cyclic ethers is accomplished by the presence of rhodium complexes. Rhodium complexes catalyze silylformylation of acetylenes leading to β-silylacrylaldehydes. The reaction of acetylenes with HSiR₃ and CO is applied to the preparation of β-lactones, β-lactams, bicyclo[3.3.0]octenones, and so on. C-Formylation of aldehydes takes place in the presence of a rhodium catalyst. Rhodium complexes also catalyze the regioselective incorporation of CO into enamines. The reaction of N,N-acetals with HSiR₃ and CO in the presence of rhodium complexes leads to several types of CO-incorporating transformations, depending on the structure of the substrates. The iridium-catalyzed reaction of olefins with HSiR₃ and CO gives acylsilane derivatives. Ruthenium complexes catalyze the conversion of 1,6-diynes to catechol derivatives, in which two molecules of CO are incorporated. Various types of new catalytic reactions have been developed by the use of the reagent combination of HSiR₃ and CO, many of them being useful in organic synthesis.

carbon monoxide - hydrosilane - cobalt - iridium - rhodium - ruthenium