Studies on the syntheses of heterocyclic compounds containing benzopyrone. Part 6. Biomimetic total synthesis of citromycetin

Abstract

Biomimetic total synthesis of citromycetin (1a) is described. Regioselective cyclization of the enetrione (5), chosen as a common intermediate for the syntheses of citromycetin (1a) and fulvic acid (2a), with conc. HCI–AcOH (1:30) gave the chioromethylpyrone (7b). Oxidation, followed by demethylation of the substituents of the pyranobenzopyranone obtained by debenzylation and cyclization of the reactive intermediate (5), yielded citromycetin (1a).