Asymmetric C-P Bond Formation Using Phosphine Electrophiles

Significance

Jørgensen and co-workers report a catalytic asymmetric phosphination using phosphine electrophiles (see Review below). By using the dimeric cinchona alkaloid derivative (DHQD)₂PYR as the catalyst, the desired α-phosphinated cyano-acetates 3 could be obtained with high enantiomeric excess. Moreover, the obtained products 3 can be transformed into protected α-phosphino β-amino acids 4 without loss of enantiopurity. The proposed mechanism shows nucleophilc activation of phosphine chloride by quinuclidine to form the N⁺-P bond.

Review: For a review on organocatalytic synthesis of organophosphorus compounds, see: Ł. Albrecht, A. Albrecht, H. Krawczyk, K. A. Jørgensen Chem. Eur. J. 2010, 16, 28-48.