The singlet excited state of a stable dialkylsilylene is responsible for its photoreactions

Abstract

The singlet 1,1-diradical (1B1) state of a silylene plays a key role in its photoreactions with benzenes and alkenes, even though similar 1B1 states are rarely encountered in carbene chemistry. The photochemical addition to alkenes should be stepwise and the ring closure of the intermediate singlet 1,3-diradicals was very facile with rates (kc) of more than 109 s-1 (see scheme).