Dimerization and Isomerization Reactions of α-Lithiated Terminal Aziridines

The scope of dimerization and isomerization reactions of α-lithiated terminal aziridines is detailed. Regio-
and stereoselective deprotonation of simple terminal aziridines with lithium 2,2,6,6-tetramethylpiperidide
(LTMP) or lithium dicyclohexylamide (LiNCy2) generates trans-α-lithiated terminal aziridines. These
latter species can then undergo dimerization or isomerization reactions depending on the nature of the
N-protecting group. α-Lithiated terminal aziridines bearing N-alkoxycarbonyl (Boc) protection undergo
N- to C-[1,2] migration to give N−H trans-aziridinylesters. In contrast, aziridines bearing N-organosulfonyl
[tert-butylsulfonyl (Bus)] protection undergo rapid dimerization to give 2-ene-1,4-diamines or, if a pendant
alkene is present, diastereoselective cyclopropanation to give 2-aminobicyclo[3.1.0]hexanes. All of these
reactions were used as key steps in the preparation of synthetically and biologically important targets.