HYDRIDE TO CARBENE MIGRATION IN THE CPMH(=C(OET)PH)(CO)2 (M = MO, W) SYSTEM AND SUBSEQUENT REARRANGEMENT OF THE CONSEQUENT PRODUCTS TO ETA-3-BENZYL COMPLEXES - X-RAY CRYSTAL-STRUCTURE OF THE ETA-3-BENZYL CPW(CO)2(ETA-3-C6H5CH(OET))

Addition of acetic acid to solution of the anions [CpM{ = C(OEt)Ph}(CO)2]- (M = Mo or W) affords the crystallographically characterized (M = W) eta-3-benzyl complexes CpM{eta-3-C6H5CH(OEt)}(CO)2. These reactions involve hydride to carbene migration within the primary products CpMH{ = C(OEt)Ph}-(CO)2 to form Cp activated M{eta-2-CH(Ph)OEt}(CO)2, the O-M bond in which is cleaved intramolecularly by the Ph group to give the eta-3-benzyl species.