Oxidative Addition of Secondary Phosphine Oxides through Rh(I) Center: Hydrido‐Phosphinito‐Rh(III) Complexes and their Catalytic Activity in Hydrophosphinylation of Alkynes

The reaction of [Rh(μ-Cl)(cod)]2 with diimines, differing in their steric and electronic properties, diphenylphosphine oxide leads to the oxidative addition products, hydrido-phosphinito-Rh(III) complexes {Rh(PPh2OH)(PPh2O)(NN)(H)Cl} (1), stabilized by formation a hydrogen bonded phosphinous acid-phosphinito quasi-chelate [(PO⋅⋅⋅HOP)-κ2P]. Exchange hydride chloride afford {Rh(PPh2OH)(PPh2O)(NN)Cl2} (2) occurs hydrido containing low hindrance diimines is inhibited for encumbered diimines. Complexes 1 react BF3⋅OEt2 exchange acidic proton BF2, transformation quasi-chelating PO⋅⋅⋅HOP into chelating PO-BF2-OP ligand {Rh{(PPh2O)2BF2}(NN)(H)Cl} (3). [Rh(μ-Cl)(nbd)]2 or [Rh(acac)(nbd)] coordinatively unsaturated nortricyclyl-phosphinito-Rh(III) complexes, {Rh(PPh2OH)(PPh2O)(ntyl)(μ-Cl)}2 (4) {Rh(PPh2OH)(PPh2O)(ntyl)(acac)} (6), respectively. Their results corresponding {Rh{(PPh2O)2BF2}(ntyl)(μ-Cl)}2 (5) {Rh{(PPh2O)2BF2}(ntyl)(acac)} (7). Some these new have shown catalytic activity hydrophosphinylation alkynes, NN being efficient regioselective catalysts phenylacetylene produce (E)-diphenyl(styryl)phosphine oxide.