A simple route to an enantiomerically pure diphosphine ligand containing a phosphorus stereogenic centre.

Abstract

The (+)- and (-)- forms of 5-(diphenylphosphino)-2,3-dimethyl-7-phenyl-7-phosphabicyclo[2.2.1]hept-2-ene have been prepared enantioselectively via an asymmetric Diels-Alder reaction between diphenylvinylphosphine and 1-phenyl-3,4-dimethylphosphole (DMPP) using 0.5 equiv of (R)-(-)- and (S)-(+)-bis(μ-chloro)bis[1-[1-(dimethylamino)ethyl]-2-naphthalenyl-C,N]dipalladium(II), respectively, as the chiral catalyst. The enantiomeric purity of the diphosphine ligand has been confirmed by 1H and 31P NMR studies. © 1994.