Stereoselective functionalization of 2-(1-aminoalkyl)aziridines via lithiation of aziridine-borane complexes

Highly selective functionalization of the aziridine ring of (2S,1'S)-2-(1'-aminoalkyl)aziridines 1, through successive formation of aziridine-borane complexes, lithiation, treatment with a variety of electrophiles and final decomplexation is described. The influence of the structure of the starting complexes 2 and of the electrophiles in the stereoselectivity of this process has been studied. Finally, successive double lithiation-electrophile reactions were carried out affording enantiopure 1,2,3,3-tetrasubstituted aziridine-borane complexes with high selectivity.