Reaction between benzaldehyde and methyl alpha-benzylsulfonylacetate f
urnishes methyl (E)-alpha-benzylsulfonyl-beta-phenylacrylate as the ex
clusive Knoevenagel adduct. The related condensations between alpha-be
nzylsulfonylacetonitrile and paraformaldehyde furnish benzylsulfonyl-2
-phenylcyclopropane-1-carbonitrile in modest yields. These product str
uctures are established by X-ray crystallographic analysis. Phenylsulf
ene is ruled out as an intermediate in the formation of the cyclopropa
ne.