Hydrometallation (M = Al, Ga) of Silicon- and Germanium-centred Oligoalkynes

摘要

Treatment of a variety of alkyl- and arylsilanes, R4-nSi(Ca equivalent to C-R')(n) and -germanes, R4-nGe(C equivalent to C-R') (1-7), with equimolar quantities of the dialkylmetal hydrides HMR ''(2) (M = Al, Ga; R '' = CMe3, CH(2)CHMe2()) yielded by reduction of a single alkynyl group a series of mixed alkenyl-alkynyl compounds R4-nSi(C equivalent to R')(n-1){C(MR ''(2)) =CHR'} (n = 2, 3) and R2Ge(C equivalent to C-R') {C[M(CMe3)(2)]=CHR' (8-13). Reactions with two equivalents of the hydrides afforded the dialkenyl compounds R2E{CUM(CMe3)(2)]=CHR ''(2) (E = Si, Ge, 14-17), Ge(C equivalent to-C CMe3)(2){C[Ga(CMe3)(2)]=CH CMe3}(2) (18) and MeSi(C equivalent to C-p-Tol) C [Ga(CMe3)(2)] =CH-P-Tol}(2) (19) fR -= Ph, Mes, Me, C6F5; = CMe3, Ph). Most of the products were characterised by X-ray crystallography which for the alkenyl-alkynyl derivatives revealed short intramolecular contacts between the coordinatively unsaturated metal atoms and the a-C atoms of unreacted ethynyl groups