Formation of silanethiols by reaction of silanes with carbonyl sulfide: implications for radical-chain reduction of thiocarbonyl compounds by silanes

Carbonyl sulfide reacts with organosilanes at 60–85°C, in the presence of a radical initiator, to give the corresponding silanethiols. Triphenylsilane is confirmed as an excellent replacement for tributyltin hydride in the Barton–McCombie deoxygenation of alcohols via their xanthates under mild conditions. Reduction of xanthates by silanes can produce COS as a by-product, leading to the in situ formation of silanethiol that will then act as a protic polarity-reversal catalyst for the reduction.