The reactivity of (Me3Si)3SiH with sulfoxides under free radical conditions

Abstract

The radical-initiated reaction of (Me3Si)3SiH with a variety of sulfoxides has been investigated. The reactivity varies significantly with the nature of the starting materials. The reactions of diaryl sulfoxides provide the corresponding sulfides in high yields while the related reactions with dialkyl sulfoxides occur more slowly and in moderate yields. The rate constant for the addition of (Me3Si)3Si radical with dibutyl sulfoxide is in the range 103–104 M−1 s−1at 80 °C. The reactivity of (Me3Si)3SiH with 1,3-dithiolane derivatives has also been investigated in a comparative study. The 2,2-dimethyl-1,3-dithiolane and the corresponding 1,1-dioxide give very smooth reaction with (Me3Si)3Si radical attack at sulfur followed by the ring opening at S–CMe2 bond and subsequent H-abstraction from the silane in very high yield, whereas the 2,2-dimethyl-1,3-dithiolane-1-oxide behaves quite differently and unexpectedly.