Hydrophosphination of α,β-unsaturated esters by primary phosphine-boranes; a useful entry to symmetrical and unsymmetrical phosphine-boranes

Article abstract of DOI:10.1016/S0040-4039(97)00247-5

The reactivity of primary phosphine-boranes RPH₂·BH₃ (R = Ph and Me) towards CH₂=CHCO₂Me and CH₂=CHP(O)(OMe)₂ is discussed. Hydrophosphination is the major process. presence of the free phosphine (0-20%) in the crude media indicates that a competitive hydroboration reaction also occurs. The P-H addition was found to be controllable to give, in reasonable yields, either the mono or the bis-adducts. All the adducts are stable and are fully characterized. The preparation of unsymmetrical bis-adduct is also presented.