A Convenient Preparation of Enantiomerically Pure (+)‐(1R,2R)‐ and (−)‐(1S,2S)‐1,2‐Diamino‐1,2‐diphenylethanes

A gram‐scale preparation of (1S,2S)‐ and (1R,2R)‐1,2‐diamino‐1,2‐diphenylethanes, (1S,2S)‐1 and (1R,2R)‐1, is reported via (±)‐iso‐amarine 4. Strategically, the activation of (±)‐iso‐amarine 4 for hydrolysis to the required diamines and enantiomeric resolution is achieved simultaneously by formation of two separable diastereoisomeric N‐acylamidines 5 and 6 derived from direct DCC‐mediated coupling of (±)‐iso‐amarine 4 with (R)‐acetylmandelic acid. iso‐Amarine 4 is conveniently obtained from amarine 3, and a one‐pot synthesis of the latter is reported from benzaldehyde and hexamethyldisilazane as catalysed by benzoic acid.