Studies On Cross Dehydrogenative Coupling Of N=C–H Bonds In Non–aromatic N–heterocycles With Si–H Bonds

Alkenylsilanes compounds are important organic compounds,which are widely used in silicon–containing organic materials and as coupling reagents in organic synthesis reactions.At present,the cross dehydrogenative coupling of C(sp²)–H bonds in ene–containing compounds with Si–H bonds is a direct,economical,and effective method for the synthesis the compounds.Non–aromatic N–heterocyclic compounds,containing C=N bonds are important organic functional molecules,forexample:quinoxalinones,benzoxazin–2–ones,N–alkyl–5,6–diphenylpyrazine–2(1H)–ones.Recently,the research on the dehydrogenative coupling of N=C–H bonds of the non–aromatic N–heterocyclic compounds has been extensive.In this paper,we have studied the cross dehydrogenative coupling of N=C–H bonds in non–aromatic N–heterocycles with Si–H bonds and the functional alkenylsilanes compounds have been synthesized.The specific contents and research results are as follows:(1)A new method of copper–catalyzed cross dehydrogenative coupling of N=C–H bonds in non–aromatic N–heterocycles with Si–H bonds to construct alkenylsilanes was developed.The optimal conditions for the reaction are:1.0 equiv quinoxalinones,benzoxazin–2–ones,N–alkyl–5,6–diphenylpyrazine–2(1H)–ones,6.0equiv silanes,20 mol%Cu Cl₂,3.0 equiv TBPB(tert-butyl benzoyl peroxide),1.0equiv KHCO₃,Ph CF₃ as solvent,under nitrogen atmosphere at 100 ^oC for 12 h.The method uses cheap and readily available Cu Cl₂ as the catalyst,avoiding noble metal catalysts,and is highly economical.The reaction is convenient to operate and has a wide range of substrates,good tolerance of functional groups,and the yields of reaction is good.(2)A new method of visible photo–catalyzed cross dehydrogenative coupling of N=C–H bonds in non–aromatic N–heterocycles with Si–H bonds to construct alkenylsilanes was developed.The optimal conditions for the reaction are:1.0 equiv quinoxalinones,benzoxazin–2–ones,N–alkyl–5,6–diphenylpyrazine–2(1H)–ones,6.0 equiv silanes,1.0 mol%Na₂Eosin Y,3.0 equiv TBPB,1.0 equiv Na₂CO₃,Ph Cl as solvent,under nitrogen atmosphere,room temperature and blue lamp irradiation for 24 h.The reaction produces various aza-vinyl silanes in good to high yields with good functional group tolerance,and features that transition metal-free,room temperature,easy operation conditions.