Stereochemistry of Palladium-Mediated Synthesis of PAMP−BH₃: Retention of Configuration at P in Formation of Pd−P and P−C Bonds

Abstract

Treatment of Pd((S,S)-Chiraphos)(o-An)(I) (3, o-An = o-MeOC6H4) with either enantiomer of highly enantioenriched PH(Me)(Ph)(BH3) (1) gave the phosphido-borane complex Pd((S,S)-Chiraphos)(o-An)(P(Me)(Ph)(BH3)) (4) with retention of configuration at phosphorus, as shown by X-ray crystal structure determinations for both diastereomers of 4. Heating either diastereomer of 4 with diphenylacetylene gave Pd((S,S)-Chiraphos)(PhCCPh) (5) and P(o-An)(Me)(Ph)(BH3) (2) with retention of configuration at phosphorus.