Assessment of Double-Barrelled Heck Cyclizations as a Means for Construction of the 14-Phenyl-8,9-dihydro- 6H-[1]benzopyrano[4′,3′:4,5]pyrrolo[2,1-a]isoquinolin- 6-one Core Associated with Certain Members of the Lamellarin Class of Marine Natural Product

Abstract

The 1,2,4-trisubstituted pyrrole (4), which is readily prepared from pyrrole itself, undergoes double- barrelled Heck cyclizations to give, inter alia, compounds (3) and (17) for which crystal structures have been determined. Product (3) constitutes the core associated with several key members, e.g. (1) and (2), of the lamellarin class of marine alkaloid.