Synthesis and structures of o-(dihydrosilyl)(dimesitylboryl)benzenes

O-(Dihydrosilyl)(dimesitylboryl)benzenes 1 were prepared in 6 steps. o-Dibromobenzene was mono-lithiated with n-BuLi and reacted with chloro(dimethoxy)silanes to afford o-C6H4(Br)[SiR(OMe)2] (2) (R = Ph, Me). Bromine–lithium exchange between 2 and tert-BuLi produced o-C6H4(Li)[SiR(OMe)2] (3), which were reacted with fluoro(dimesityl)borane to give o-C6H4(BMes2)[SiR(OMe)2] (4). Reduction of 4 with LiAlH4 in THF yielded [o-C6H4(BMes2H)(SiRH2)]−Li+(thf)n (9). Treatment of 9 with BF3·OEt2 afforded the target compounds 1. The structures of 1 were determined by NMR spectroscopy and X-ray crystallographic analysis.