Novel Syntheses of 5-Aroyl-1,2-dihydro-3H-pyrrolopyrrole-1-carboxylic Acids

Article abstract of DOI:10.1021/jo00348a014

A fundamentally new approach to the synthesis of the title compounds was devised in which the crucial step was the intramolecular displacement of methanesulfinate ion or bromide ion by the sodium enolates of properly disposed substituted malonate esters such as 13a-13c and 20.As integral parts of the above process, a new four-carbon alkylation of the pyrrole nitrogen atom, a novel synthesis of 2-(methylthio)pyrroles, and the use of the dimethylsulfonium moiety as meta directing group in the pyrrole system were developed.