39. Blank, N. F.; McBroom, K. C.; Glueck, D. S.; Kassel, W. S.; Rheingold, A. L. Organometallics 2006, 25, 1742-1748. Chirality Breeding via Asymmetric Phosphination. Palladium-Catalyzed Diastereoselective Synthesis of a P-Stereogenic Phosphine.

Abstract Methylation of the crystallographically characterized primary alkylphosphine-borane PH₂Men(BH₃) (3, Men = (&endash;)-menthyl) under phase-transfer conditions, followed by deprotection, gave the secondary phosphine PH(Me)(Men) (2). Cross-coupling of 2 with PhI in the presence of NaOSiMe₃ selectively gave S_P-PPh(Me)(Men) (1, L) with a variety of Pd catalyst precursors, including a complex of diastereopure S_P-1, trans-PdL₂(Ph)(I) (6a). In this reaction, the chiral phosphine L formally acted as a ligand in catalysis of its selective self-reproduction, but 6a was partially transformed to its diastereomers, trans-Pd(S_P-1)(R_P-1)(Ph)(I) (6b) and trans-Pd(R_P-1)₂(Ph)(I) (6c), and several other intermediates were observed during catalysis.