Novel rhodium-1,3-dialkylperhydrobenzimidazolin-2-ylidene (2a,b) and 1,3-dialkylimidazolin-2-ylidene complexes (4a,b) have been prepared and characterized by C, H, N analysis, H-1 NMR and C-13 NMR. Triethylsilane reacts with acetophenone derivatives in the presence of catalytic amount of the new rhodium(I)-carbene complexes, RhCl(COD)(1,3-dialkylperhydrobenzimidazolin-2-ylidene) or RhCl(COD)(1,3-dialkylimidazolin-2-ylidene) to give the corresponding silylethers in good yields (63-99%). (c) 2005 Elsevier B.V. All rights reserved.