Synthesis of Cyclic Alkyl(amino) Carbene Stabilized Silylenes with Small N-Donating Substituents.

Lewis base cAACs stabilized monomeric silylenes with halogen or methyl substituents at the silicon center have not been reported due to the strong σ-donor and π-acceptor character of cAAC. To prepare these monomeric silylenes, we used the silicon(IV) precursors 5 and 6 with a nitrogen donor group L (L=o-C H NMe ). The cAAC-stabilized (cAAC=C(CH )(CMe ) N-Ar, Ar=2,6-iPr C H ) silylenes LSiCl(cAAC) (7) and LSiMe(cAAC) (8) were synthesized by reduction of LSiCl and LSiMeCl with two equivalents of KC in the presence of one equivalent of cAAC, respectively. Compounds 7 and 8 were characterized by single-crystal X-ray crystallography, NMR spectroscopy, and elemental analysis. Compounds 7 and 8 are stable in the solid state as well as in solution at room temperature for at least four months under inert conditions.