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Abstract
The reaction of {CpFeCO{P(OPh)(,3)}((eta)('2)-MeC(TBOND)CMe}('+) with Ph(,2)Cu(CN)Li(,2) yields CpFeCO{P(OPh)(,3)}{E-C(Me)=C(Me)Ph} whereas the reaction of {CpFeCO{P(OPh)(,3)} ((eta)('2)-MeC(TBOND)CMe}('+) with Me(,2)Cu(CN(Li(,2) yields CpFeCO{P(OPh)(,3)}{Z-C(Me)=C(Ph)Me}, the product of the latter being characterized by X-ray crystallography. These alkenyl products will not interconvert under the conditions of the reactions. Thus, trans-addition of these nucleophilies to (eta)('2)-alkyne complexes is definitively demonstrated for the first time and is presented in Chapter I. Yields in these reactions are high, demonstrating for the first time the usefulness of higher order organocuprate reagents for addition reactions to unsaturated organic ligands II-coordinate to transition metals.
Chapter II examines the reaction of {CpFeCO(L) ((eta)('2)-alkyne)}BF(,4) (L = PPh(,3), P(OPh)(,3)) complexes with a variety of nucleophilic reagents which leads to a large family of CpFeCO(L)((eta)('1)-alkenyl) dervatives. Carbon based nucleophiles are generally best delivered from R(,2)Cu(CN)Li(,2) type reagents and include R = Me, Ph, CH=CH(,2) and C(TBOND)CMe. The reagents Na{CH(CO(,2)Et)(,2)}, KCN (or better R(,4)NCN) and NaSPh are also successful in the alkyne addition reactions. All the nucleophiles add trans. The CpFeCO{P(OPh)(,3)}((eta)('1)-E-C(Me)=C(Me)Nuc} complexes show dynamic NMR behavior. At low temperatures, two rotamers of the alkenyl group about the Fe-C (alkenyl) bond are observed and these equilibrate near ambient temperature.
X-ray structural analysis has shown that the product of the reaction of {HB(sec-Bu)(,3)}('-) and {((eta)('5)-C(,5)H(,5))FeCO(PPh(,3))((eta)('2)-MeC(TBOND)CCO(,2)Et}('+) is ((eta)('5)-C(,5)H(,5)FeCO(PPh(,3))((eta)('1)-E-C(CO(,2)Et)=C(H)Me. Analysis using ('1)H, ('13)C and ('2)H NMR spectroscopy has shown the reaction of {DBEt(,3)}('-) with {((eta)('5)-C(,5)H(,5)FeCO(L) ((eta)('2)-MeC(TBOND)CCO(,2)Me)}('+) (L = PPh(,3), P(OPh)(,3)) or {((eta)('5)-C(,5)H(,5))FeCO{P(OPh)(,3)}((eta)('2)-MeC(TBOND)CPh)}('+) leads to similar products in which added deuterium is found in a C(,5)H(,4)D ring of the product with no deuterium on the vinyl ligand. Thus, cis addition to the (eta)('2) alkyne takes place by inital addition of the hydride (deuteride) to the (eta)('5)-C(,5)H(,5) ring followed by internal hydrogen atom transfer to the alkyne.
The reaction of {CpFeCO{P(OPh)(,3)}((eta)('2)-allene)}BF(,4) with a series of nucleophiles leads to a family of CpFeCO{P(OPh)(,3)}((eta)('1)-C(CH(,2)Nuc)=CH(,2)} complexes. Stirring these complexes in CHCl(,3) or with alumina leads to an overall 1,3-hydrogen shift to yield new complexes of the type CpFeCO{P(OPh)(,3)} ((eta)('1)-E-C(Me)=C(H)Nuc}. This rearrangement is observed for Nuc = CH(,3), H, Me, Ph, SPh, CH=CH(,2), and C(TBOND)CMe, and is discussed in Chapter IV.
