P-H bond activation of primary phosphine-boranes: Access to α-hydroxy and α,α′-dihydroxyphosphine-borane adducts by uncatalyzed hydrophosphination of carbonyl derivatives

Article abstract of DOI:10.1016/S0022-328X(96)06640-5

Primary P-phenyl and P-methyl phosphine-boranes 1 and 2 are prepared by complexation of the free phosphines with BH₃ · SMe₂. They are stable and can be purified by distillation. Under basic conditions, they lead selectively to secondary alkylphosphine-boranes and under neutral conditions to the corresponding mono- and bis-hydroxyphosphine-boranes 5 and 6. All these new compounds are purified by chromatography on silica gel. A competitive hydroboration induced by the decomplexation of BH₃ is observed as a minor process. Conditions for the decomplexation of phosphine-borane adducts are presented.