A 1,2-Dibromosilene: Generation, spectroscopic observation, and isomerization to a silacyclohexane via facile 1,2-bromine shift

1,2-Dihalosilene is a hitherto unknown but potentially useful functionalizable compound for new silenes and silicon-carbon triply bonded species. We successfully generate 1,2-dibromosilene 1 by the reaction of tetrabromo derivative 2 with BuLi. The formation of 1 is confirmed by NMR studies and trapping experiments. Silene 1 survives under -80 °C, but 1 thermally isomerizes to silacyclohexane 6 via a 1,2-bromine shift to form bis(silyl)carbene 11 and the subsequent intramolecular C-H insertion.