Regioselective electrophilic substitution of 2,3-aziridino-γ-lactones:: preliminary studies aimed at the synthesis of α,α-disubstituted α- or β-amino acids

2,3-Aziridino-gamma-lactones are versatile synthons for the preparation of polysubstituted alpha- or beta-amino acids. With the intention of preparing alpha,alpha-disubstituted alpha- or beta-amino acids, regioselective electrophilic substitution of aziridino-gamma-lactones at C2 was realized using two different methods. In the first, the anion was generated at C2 with LDA in the presence of the electrophilic agent. In the second method, the anion was trapped with TMS. Subsequent treatment of the C2 silylated product with a fluoride ion source regenerated the anion, which then reacted in situ with various electrophiles. Intramolecular aziridine opening of the C2 benzyl derivative prepared by the first method allowed access to a novel furan derivative, a direct precursor of an alpha,alpha-disubstituted beta-amino acid. (c) 2007 Elsevier Ltd. All rights reserved.