Silane–Isocyanide Coupling Involving 1,1-Insertion of XylNC into the Si–H Bond of a σ‑Silane Ligand

Complexes [PhBPPh3]­RuH­(η3-H2SiRR′) (R,R′
= Me,Ph, 1a; RR′ = Ph2, 1b) react with XylNC
(Xyl = 2,6-dimethylphenyl) to form Fischer carbene complexes [PhBPPh3]­Ru­(H)[C­(H)­(N­(Xyl)­(η2-H–SiRR′))] (2a,b) that feature
a γ-agostic Si–H bond. The ruthenium isocyanide complexes
[PhBPPh3]­Ru­(H)­(CNXyl)­(η2-HSiHRR′)
(6a,b) are not intermediates as they do
not convert to 2a,b. Experimental and theoretical
investigations indicate that XylNC is activated by initial coordination
to the silicon center in 1a,b, followed
by 1,1-insertion into an Si–H bond of the coordinated silane
and then rearrangement to 2a,b.

配合物[PhBPPh₃]RuH(η³-H₂SiRR')（R,R'=Me,Ph时记为1a；RR'=Ph₂时记为1b）与XylNC（Xyl=2,6-二甲基苯基）反应，生成费舍尔卡宾配合物（Fischer carbene complex）[PhBPPh₃]Ru(H)=[C(H)(N(Xyl)(η²-H–SiRR'))]（2a,b），该类配合物带有γ-agostic硅氢键（γ-agostic Si–H bond）。钌异氰配合物[PhBPPh₃]Ru(H)(CNXyl)(η²-HSiHRR')（6a,b）并非该反应的中间体，因其无法转化为2a,b。实验与理论研究表明，XylNC的活化始于其与1a,b中的硅中心配位，随后发生1,1-插入反应进入配位硅烷的Si-H键，最终重排得到2a,b。