Synthesis of a Dimeric Base‐Stabilized Cobaltosilylene Complex for Catalytic C−H Bond Functionalization and C−C Bond Formation

Abstract

Abstract The synthesis of a dimeric base‐stabilized cobaltosilylene complex and its catalytic reactions are described. Treatment of the amidinato silicon(I) dimer [LSi:] 2 ( 1 ; L=PhC(N t Bu) 2 ) with CoBr 2 in toluene for 10 days afforded the dimeric amidinato cobaltosilylene [(LSi) μ ‐{CoBr(LSiBr)}] 2 ( 2 ), which is speculated to proceed via “LSiCoBr” and “LSiBr” intermediates in the reaction. Compound 2 is paramagnetic, with an effective magnetic moment of 2.8 μB. Its electronic structure was elucidated by single‐crystal X‐ray crystallography and DFT studies. It was capable of catalyzing C−H bond functionalization, in which a combination of 2 , phosphine and MeMgI can regio‐ and stereoselectively promoted the addition of the C≡C triple bonds in alkynes to the ortho ‐C−H position in arylpyridines. In addition, compound 2 catalyzed Kumada‐type coupling reactions between aryl chlorides and the Grignard reagent 2‐mesitylmagnesium bromide.