Pyrrole-singlet oxygen reactions leading to α,α′-bipyrroles. Synthesis of prodigiosin and analogs

Abstract

Reaction of the tert-butyl ester of 3-methoxy-2-pyrrolecarboxylic acid with singlet oxygen yields a hydroperoxide intermediate which undergoes coupling with pyrroles to yield precursors of prodigiosin and ring A analogs, readily convertible to the corresponding tripyrromethenes.