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

Isolable alpha-amino N-tert-butanesulfinimines were prepared through the condensation of Reetz's alpha-amino aldehydes (prepared from alpha-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.