Diastereo- and enantioselective synthesis of γ- and- δ-lactams bearing a propionic acid α-side-chain via Michael addition of N-dialkylamino lactams to enoates

Article abstract of DOI:10.3987/COM-99-S83

γ- and- δ-Lactams [(R,R)-5a-e] bearing a propionic acid α-side-chain were synthesized in good overall yields (38 - 58 %, two steps) and diastereo- and enantiomeric excesses (de = ≥ 96%, ee = 90 - ≥ 96%) by 1,4-addition of metalated N-dialkylamino lactams [(S)-2a,b] to enoate Michael acceptors (3) followed by saponification of the ester group and subsequent removal of the chiral auxiliary by reductive cleavage of the N-N-bond with lithium in liquid ammonia.