Jm. Chong et al., ASYMMETRIC-SYNTHESIS OF TRANS-2,5-DIPHENYLPYRROLIDINE - A C-2-SYMMETRICAL CHIRAL AMINE, Tetrahedron : asymmetry, 6(2), 1995, pp. 409-418
(R,R)-2,5-Diphenylpyrrolidine of high enantiomeric purity (>98% e.e.)
may be prepared from 1,4-diphenyl-1,4-butanedione in 4 steps and 64% o
verall yield. A key step is asymmetric reduction of the dione with Ipc
(2)BCl.