Indenylidene‐Ruthenium Complexes Bearing Saturated N‐Heterocyclic Carbenes: Synthesis and Catalytic Investigation in Olefin Metathesis Reactions

Abstract

Abstract The synthesis of complexes of the general formula Cl 2 Ru(SIMes)(L)(3‐phenylinden‐1‐ylidene) ( 5 , L = PCy 3 ; 6 , L = py; and 7 , L = PPh 3 ) from Cl 2 Ru(PR 3 ) 2 (3‐phenylinden‐1‐ylidene) ( 2a , R = Ph; 2b , R = Cy) is reported. This family of olefin metathesis catalysts was fully characterized ( 1 H, 13 C and 31 P NMR spectroscopy and elemental analysis) and provided excellent activity in the ring‐opening metathesis polymerization of 1,5‐cyclooctadiene and the ring‐closing metathesis of diethyl diallylmalonate. Comparison with the corresponding benzylidene‐containing catalysts, 1a , c and 8b , established the decisive role of the carbene ligand on the procedure of the reaction and led to the observation of an unusual catalytic phenomenon, here called “self‐inhibition”.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)