Stereocontrol in the reduction of 1,2-diimine with an oxazaborolidine catalyst. Highly stereoselective preparation of (R,R)-1,2-diphenylethylenediamine

Article abstract of DOI:10.1016/0040-4039(95)01825-3

Highly enantioselective reduction of 1,2-bis(p-methoxyphenylimino)-1,2-diphenylethane was conducted even with 0.5 mol% of new oxazaborolidine derived from L-threonine and a stoichiometric amount of BH₃·THF to give 1,2-diphenylethylenediamine derivative in excellent enantiomeric purity. The subsequent deprotection of nitrogen atoms afforded (R,R)-1,2-diphenylethylenediamine in enantiomerically pure form.