Reactions of 1-arylbenzo[b]thiophenium salts with methoxide anion in methanol caused the fission of the S+-C(2) bond of the thiophenium ring to produce o-(phenylthio)phenyl-substituted methoxyethenes, allenes, or alkynes.
Photolysis of 1-phenylbenzo[b]thiophenium salts was conducted by use of a Pyrex-filtered high-pressure Hg lamp. The major products in most cases were the phenyl-migrated ones, i.e., 2-phenylbenzo[b]thiophenes and 3-phenylbenzo[b]thiophenes, together with the dephenylated benzo[b]thiophenes. This photochemical behavior is quite different from the thermal ones that provide the ring-opened olefins. The