Chemistry of pyrrocorphins: synthesis of isobacteriochlorins and pyrrocorphins bearing a methyl group at the meso position between rings A and D

Abstract

A sigmatropic methyl shift from the angular position C-1 in ring A to the meso position C-20 between rings A and D constitutes the crucial step in syntheses leading to a 20-methyl-isobacteriochlorin and to 20-methyl-pyrrocorphins which served as substrates in the investigation presented in the accompanying communication.