Chiral, nonracemic o-aminobenzylamines were prepared in a highly diastereoselective reduction of atropisomeric N-tert-butanesulfinylketimines. The ortho-substituent ensures the distinct reactivity of atropisomers 4d− f. The free energy of activation for atropisomerization of sulfinylimines 4d− f in THF-d 8 was determined by NMR methods to range from 70.8 to 97.9 kJ/mol.
