RUTHENIUM ALKOXYCARBENE COMPLEXES FROM AN ACETAL FUNCTION BY C-O BOND-CLEAVAGE AND ALCOHOL ELIMINATION

Heating solutions of acetal complexes (CH3CN)(2)[eta(1)-P-2-(Ph(2)P)[C H(OR)(2)]C6H4]}OTf (3; R = Me, Et) at 60-95 degrees C results in loss of one CH3CN ligand and the alcohol ROH, with concomitant formation of carbene complexes CpRu(CH3CN)[eta(2)-C,P-2-(Ph(2)P)[C(OR)]-C6H4]}OTf (4) in high yield. Kinetic and reactivity studies suggest that the rat e-determining step of the conversion of 3 to 4 is oxidative addition o f an acetal C-O bond to the ruthenium center, which occurs under neutr al, mild conditions.