Role of the Base in Dehydrocoupling Reaction of Phenylsilane with Methanol

Catalytic dehydrocoupling of silanes with alcohols is possible without an additional solvent, and the conversion efficiency depends on the properties of the silane, alcohol, and catalyst. We have shown that in low-polarity solvents, the key intermediates in the reaction of hydrosilanes with fluorinated alcohols (HORF) are tetrel compounds [R4–nSi(ORF)Hn]–, containing pentacoordinated (hypervalent) silicon, and their dihydrogen-bonded complexes of the type [R4–nSi(ORF)Hn]–···HORF. However, the dehydrocoupling reaction was not observed when using less acidic, non-fluorinated alcohols as substrates. This work presents the results of a study on the possibility of a solvent-free dehydrocoupling reaction with aliphatic alcohols using the PhSiH3–MeOH system as an example in the presence of Et3N, as well as palladium and nickel complexes with the pincer ligand (PNP)MX [M = Ni, Pd; X = Cl, H; PNP = bis-(2-diisopropylphosphino-4-methylphenyl)amide], in which the basicity of the amide nitrogen atom approaches the basicity of triethylamine.