Radical-Initiated Dismutation of Hydrosiloxanes by Catalytic Potassium-Graphite

Formation of higher-value products from cheaper silicone precursors such as polymethylhydrosiloxane (PMHS) is a challenge for silicon chemistry. Here, we show that catalytic amount (<0.5 mol %) of potassium graphite (KC₈) can be used as an efficient radical initiator for the cleavage of Si−O bonds of hydrosiloxanes. Methylsilane and dimethylsilane are quantitatively obtained from PMHS and TMDS (1,1,3,3-tetramethyldisiloxane), respectively. Taking advantage of the high reactivity of the newly formed silane, the reduction of carbonyl functionalities with KC₈ in catalytic amount was further performed. Mechanistic investigations suggest that both the dismutation of the initial hydrosiloxane and the reduction of carbonyl derivatives by hydrosilylation are initiated with a radical pathway.