The reaction of N-magnesium derivatives of pyrroles with N-mesylchloromethylpyrroles: A synthesis of dipyrrylmethanes

Attachment of an alkyl- or arylsulfonyl group at the nitrogen atom of a pyrrole reduces the aromaticity and electron availability of the system. This is confirmed by the structure of an N-tosylated chloromethylpyrrole determined by X-ray crystallography. In agreement, N-mesylated chloromethylpyrroles are handleable materials which react smoothly with N-magnesium derivatives of pyrroles to provide a novel route for synthesis of dipyrrylmethanes. Several examples of this synthesis are described, including the construction of molecules carrying deuterium at the interpyrrolic methylene group.