Figure 1.
(A) Reaction catalyzed by IPNS in the formation of the penicillin nucleus. (B) Mechanism proposed by Baldwin and co-workers for the IPNS reaction [9]. (C) Aberrant reactions occurring with ACV derivatives containing either d-α-hydroxyisovalerate [18] or 3,3-[2H]2-d-aminobutyrate in place of d-valine [8].