Tertiary sulfanylphosphine and aminoalkylphosphine oxides can be easily converted into the corresponding tertiary sulfanylphosphine- and aminoalkylphosphine-boranes, respectively, through the facile P=O bond reduction by borane complexes. The easy reduction of the strong P=O bond by BH₃, a mild reducing agent, has been achieved through an intramolecular P=O -- B complexation directed by proximal SH or NH activating groups located at the α- or β-position to the P=O bond. A generalized reduction mechanism has been proposed.

The secondary phosphine oxide, t-BuPhHP=O, the most prominent chiral member of this compound class, has been resolved in high yield and with excellent ee. This resolution discloses an efficient route to enantiopure phosphorus compounds.

A practical protocol for efficient synthesis of both PAMPO enantiomers as well as related functionalised P-stereogenic phosphine oxides in 1–3 steps from effectively resolved (S _P)-l-menthyl o-anisyl­-(phenyl)phosphinylacetate has been developed. Examples of non-stereo­selective quaternisation of a tertiary phosphine by alkyl halides have been revealed.

Two synthetic protocols for the conversion of 1-phenylphosphinan-4-ones to novel P-stereogenic 1-phenylphosphin-2-en-4-ones by enantioselective deprotonation followed by oxidation and by asymmetric organocatalytic halogenation accompanied by elimination have been developed. These two-step one-pot transformations provide convenient access to optically active 1-phenylphosphin-2-en-4-one 1-sulfide and 1-phenylphosphin-2-en-4-one 1-oxide of 96 and 55% enantiomeric purities, respectively.