Dihydropyridinone approach to manzamines: An expedient construction of the tetracyclic core of manzamine A

Abstract

A construction of the central tetracyclic core ( 19) of manzamine A ( 1) was successfully achieved by a highly efficient Diels-Alder reaction of the suitably protected dihydropyridinones ( 5) and Danishefsky's diene as a key strategy. Expedient conversion of the D-A product ( 7) to the precursor ( 15) was followed by the azocine lactam ring closure to furnish the titled core.