Synthesis and Rearrangement of 2-(Arylsulfinyl)- and 2-(Alkylsulfinyl)pyrroles

Article abstract of DOI:10.1021/jo01314a025

Pyrrole and N-methylpyrrole reacted with aryl- and alkylsulfinyl chlorides, at 0 deg C, to give the corresponding 2-sulfinylpyrroles as the major products only when contact of the products with the liberated hydrogen chloride was minimized or eliminated.If this precaution was not taken, the 3-sulfinylpyrroles were the principle products.In contrast, N-(phenylsulfinyl)succinimide (2a) reacted, at room temperature, with a variety of pyrroles to produce the 2-phenylsulfinyl compounds in good yields.The 2-(arylsulfinyl)- and 2-(alkylsulfinyl)pyrroles undergo a remarkably facile acid-promoted rearrangement to the isomeric 3-sulfinylpyrroles.This transposition is, at least in part, an intermolecular process as demonstrated by crossover experiments.