Efficient total syntheses of louisianins C and D

An efficient synthetic route for the preparation of louisianins C and D was developed starting with the commercially available 4-cyanopyridine. Louisianins C and D were synthesized in seven steps and with overall yields 22% and 20%, respectively, following a novel cyclization–decarboxylation sequence involving 4-bromo-6,7-dihydrocyclopenta[c]pyridin-5-one as the key intermediate.