Reactivity of co-ordinated ligands. Part VIII. The preparation and reactivity of some rhodium(I) derivatives of tricyclo[5,2,1,02,6]deca-4,8-dien-3-one and tricyclo[6,2,1,02,7] undeca-4,9-diene-3,6-dione

Abstract

The preparation and reactions of cyclopentadienyl(tricyclo[5,2,1,0^2,6]deca-4,8-dien-3-one)rhodium(I), (dp)Rh(π-C₅H₅), and cyclopentadienyl(tricyclo[6,2,1,0^2,7]undeca-4,9-diene-3,6-dione)rhodium(I), (cq)Rh(π-C₅H₅) are described. Both complexes undergo several characteristic reactions of ketones. The ketone group of (dp)Rh(π-C₅H₅) undergoes nucleophilic attack by R^– to give the corresponding alcohol, (π-C₅H₅)Rh{C₁₀H₁₀(OH)R}(R = H, Me, Prⁱ, or CH₂·CO₂Me). These alcohols react with hexafluorophosphoric acid or triphenylmethyltetrafluoroborate to give the corresponding cations, [(π-C₅H₅)Rh(C₁₀H₁₀R)]⁺. The complex (cq)Rh(π-C₅H₅) reacts with sodium borohydride to give a diol, (π-C₅H₅)Rh(C₁₁H₁₄O₂) and with methylmagnesium iodide to give the alcohol, (π-C₅H₅)Rh(C₁₂H₁₄O₂). Reaction of these alcohols with hexafluorophosphoric acid or triphenylmethyl tetrafluoroborate gives cationic(dienyl) complexes of the type [(R²C₅H₅)Rh{C₁₁H₁₀R¹(OH)}]BF₄ and [(R²C₅H₄)Rh{C₁₁H₁₀R¹(O)}] BF₄(R¹= R²= H; R¹= H, R²= CPh₃; R¹= Me, R²= H).