Ruthenium Alkoxycarbene Complexes from an Acetal Function by C−O Bond Cleavage and Alcohol Elimination

Heating solutions of acetal complexes {CpRu(CH3CN)2[η1-P-2-(Ph2P)[CH(OR)2]C6H4]}OTf (3; R = Me, Et) at 60−95 °C results in loss of one CH3CN ligand and the alcohol ROH, with concomitant formation of carbene complexes CpRu(CH3CN)[η2-C,P-2-(Ph2P)[C(OR)]C6H4]}OTf (4) in high yield. Kinetic and reactivity studies suggest that the rate-determining step of the conversion of 3 to 4 is oxidative addition of an acetal C−O bond to the ruthenium center, which occurs under neutral, mild conditions.