Synthesis of alpha-substituted beta-amidophosphines by diastereoselective alkylation. A new access to chiral ligands for asymmetric catalysis

Chiral beta -amidophosphine boranes 7a-f can be diastereoselectively alkyla ted, using O-protected amino-alcohols as chiral inducers, to furnish alpha -substituted beta -amidophosphine boranes 8a-f and 9-12 with up to 72% dias tereoisomeric excess. Selective deprotection afforded optically pure carbox ylic derivative 13 which is a key intermediate for the synthesis of various potential chiral ligands for asymmetric catalysis.