Carbon skeleton of polysubstituted pyroglutamates with three contiguous asymmetric centers was built up in one base-induced coupling/cyclization reaction of α-sulfonylacetamide with 2-bromo-2-propenoates. A simple transformation to 3-substituted prolinols can be easily achieved via reduction and desulfonation. A ring expansion of prolinol has been used as the key step in the formal synthesis of isoguvacine and paroxetine. The one-pot conversion of 3-substituted prolinol to the 3-substituted pyroglutamic acid is also reported.
glutarimides - stepwise [3+2] annulation - pyroglutamates - prolinol - isoguvacine - paroxetine
