SYNTHESIS, DETERMINATION OF ENANTIOMERIC PURITY AND STRUCTURAL CHARACTERIZATION OF ENANTIOPURE (2R,5R)-(-2,5-BIS-(DIPHENYLPHOSPHINO)-HEXANE, A CHIRAL DPPB ANALOG())

Enantiopure (2R,5R)-(+)-2,5-bis-(diphenylphosphino)hexane, 3, a chiral analogue of 1,4-bis-(diphenylphosphino)butane was synthesized in two steps from enantiomerically pure (2S,5S)-(+)-hexanediol. The molecular structure of (2R,5R)-3 was determined by X-ray structure analysis of its nickel-(II)-complex showing a rare dimeric species; NMR analysis o f the reaction product of 3 with {2-[1-(dimethylamino)ethyl]phenyl-C,N }-dipalladium allowed to deduce the enantiomeric purity.