Readily available Ti-based in situ catalytic system for oxo/imido heterometathesis

We investigate Ti(NEt2)(4)supported on silica dehydroxylated at 700 degrees C as an easily accessible pre-catalystfor oxo/imido heterometathesis reactions. Being activated with TolNH2, the supported Ti amide(uSiO)Ti(NEt2)(3)(1) demonstrates catalytic activity in the imidation of ketones withN-sulfinylamines com-parable with the most active previously described well-defined imido catalyst (uSiO)Ti(vNtBu)(Me(2)Pyr)(py)2(2) (Me(2)Pyr = 2,5-dimethylpyrrolyl), which implies thein situformation of surface imido species inthis system. The materials obtained via treatment of1with anilines (TolNH(2)(1a) andp-(MeOC6H4NH2)-N-15(1b)) were studied with IR, EA and(1)H,C-13,N-15 and 2D solid-state NMR, although the proposed imidointermediate has not been detected, pointing towards tris-amides (uSiO)Ti(NHC6H4X)(3)(X = Me, OMe)being the major surface species in the isolated materials1aand1b. The system1/TolNH2was tested in arange of imidation reactions and demonstrated excellent performance for express high-yielding prepa-ration of ketimines, formamidines, lactone imidates and sulfurdiimines, making it a convenient alternativeto the well-defined supported Ti imido catalysts