Synthesis and Reactivity of a Stable Silylene

The synthesis and several reactions of the stable silylene 1 (1,3-di- tert -butyl-2,3-dihydro-1 H -1,3,2-diazasilol-2-ylidene) are described. X-ray crystal structures are given for two intermediates in the synthesis of 1, the diimine 7 and its dilithium salt 8, and for a byproduct, the spiro compound 10 . 1 reacts with ethanol and water by inserting into the O−H bond, and with iodomethane by insertion into the C−I bond. The silanol from reaction of 1 with water condenses to a disiloxane, 13 . From 1 and sulfur and selenium, cyclic compounds containing Si 2 E 2 rings are obtained (E = S or Se). Crystal structures are presented for disiloxane 13 and for the sulfur and selenium cycloadducts, 15 and 17 .