Generation of α-amino acid homoenolate equivalents. Synthesis of 3-substituted prolines

Article abstract of DOI:10.1016/S0040-4039(00)97924-3

Deprotonation of the N-protected aminoketene-S,S-acetal (6) and reaction of allylic anion (7) with electrophiles leads to adducts (8) which have been converted to 3-substituted prolines (11). Conformationally constrained variants (11d) and (11e) of aspartic and glutamic acid have been prepared.