The reaction of the anion of ethyl isocyanoacetate with suitably subst
ituted vinyl p-tolyl sulfones gives fair to good yields of pyrrole-2-c
arboxylates substituted in the 3-, 4- or 3- and 4-positions. From the
reaction of 1-phenyl-1-tolylsulfonylethene with ethyl isocyanoacetate,
two diastereoisomers of ethyl fonyl)-3,4,5,6-tetrahydro-2H-azepine-2-
carboxylate (4) were also isolated.