Stereocontrol in the reduction of 1, 2-diimine with an oxazaborolidine catalyst. Highly stereoselective preparation of (R, R)-1, 2-diphenylethylenediamine
Highly enantioselective reduction of 1, 2-bis (p-methoxyphenylimino)-1, 2-diphenylethane was conducted even with 0.5 mol% of new oxazaborolidine derived form 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.
