STUDIES ON ORGANOSILICON REACTIVE INTERMEDIATES .6. PHOTOLYSIS OF TRISILANES CONTAINING HETEROCYCLES

Both 2-phenyl-2-furylhexamethyltrisilane (1) and 2-phenyl-2-thienylhexamethyltrisilane (2) were synthesized by conventional organometallic reactions. The photolysis of 1 in the presence of 2,3-dimethyl-1,3-butadiene led to normal silylene-olefin addition and silylene C-H insertion reactions. However, when 2 was photolyzed in a methanol-cyclohexene system, an apparent radical reaction occurred. We suspect that the sulfur atom of the thienyl group strongly stabilizes a silyl radical. This result was supported by both identifying its typical radical reaction products and examining the ESR spectrum of its adduct with a radical trap.