C2-symmetric N,N-bis(phosphinomethyl)amines were prepared by the thermal
reaction of aromatic aldehydes with ammonia and hypophosphorus acid as previously described.
Both enantiomers of C2-symmetric N,N-bis(phosphinomethyl)amine were obtained in a high enantiomeric
purity through the diastereomeric salt formation with (–)-quinine, and subsequent fractional
crystallization. X-ray crystallographic analysis of one of the diastereomeric salts clearly
revealed that (–)-quinine could be an efficient resolving agent for obtaining the single enantiomer
(R,R)-N,N-bis(phosphinomethyl)amine.
