Reaction of silylpentacarbonylmanganese with hydride-transfer reagents: reduction of carbonyl ligands accompanied with SiC and CC coupling

Treatment of Mn(CO)5SiTolp2H (2) with an excess of LiAlH4, NaBH4, or NaBH3(CN) in THF at room temperature gave hydrosilane HSiTolp2H in high yield together with Mn2(CO)10. No reduction of CO ligands was observed. On the other hand, treatment of 2 with an excess of Red-Al (=Na[(CH3OCH2CH2O)2AlH2]) in toluene and subsequent addition of aqueous acidic solution afforded alkylsilanols (CH3)SiTolp2(OH) and (C2H5)SiTolp2(OH). Treatment of the reaction mixture of 2 and Red-Al with LiAlH4 in diethyl ether instead of hydrolysis gave alkylhydrosilanes (CH3)SiTolp2H and (C2H5)SiTolp2H. The methyl and ethyl groups on silicon originate from the CO ligands in 2. These products clearly demonstrate that not only the SiC coupling, but also CC coupling occurs efficiently in this reaction.