(2R,5S)-2,3-Diphenyl-1,3,2-diazaphosphabicyclo[3.3.0]octane-Borane

The title complex, C₁₇H₂₂BN₂P, (3), is one of a series of new chiral diazaphospholidine-borane complexes used as catalysts in the enantioselective borane reduction of ketones. We describe herein the determination of the molecular structure of (3) and the absolute configuration about the P atom.