Total Synthesis of Alkaloid Natural Products Starting with 3,5-Dibromo-2-pyrone as a Useful Building Block

Abstract

Erythrina alkaloids in the pea famliy widely distributed in the vegetable field consist of about 70 kinds of natural products and have interesting azatetracyclic structures (A, B, C, D) in common. They represent an attractive synthetic target substance for pharmacological effects including sedation, hypotension, neuromuscular blockade, and CNS activity. An erythrina alkaloid [(±)-Erysotramidine, (±)-Erysotrine, (±)-Erythramine, (±)-Erythraline] was synthesized to further expand the 2-pyrone strategy for target-directed synthesis. Here we report the strategic use of our 3,5-dibromo-2-pyrone and Diels-Alder reactions for the total synthesis of erythrina alkaloids.