Stereoselective Synthesis of Trifluoromethylated Vicinal Ethylenediamines with α-Amino N-tert-Butanesulfinimines and TMSCF₃

Isolable α-amino N-tert-butanesulfinimines were prepared through the condensation of Reetz's α-amino aldehydes (prepared from α-amino acids) with Ellman's (R)-N-tert-butanesufinamide without any racemization, and these were trifluoromethylated with TMSCF₃ and TMAF (tetramethylammonium fluoride) to the corresponding vicinal ethylenediamines derivatives. Imines derived from l-amino acids gave exclusively one diastereomer with a very high yield.