Concise and Scalable Total Syntheses of Lamellarin Z and other Natural Lamellarins: Regiocontrolled Assembly of the Central Pyrrole Core and Cross Dehydrogenative Coupling Enroute to the Pentacyclic Coumarin-Pyrrole-Isoquinoline Scaffold 

An efficient construction of the central 1,2,4-trisubstituted pyrrole core via one-pot [3+2] cycloaddition/elimination/aromatization sequence-based domino process and subsequent Pd-mediated cross dehydrogenative coupling between the C-H bonds of pyrrole and the peripheral aryl rings enables rapid access to the pentacyclic coumarin-pyrrole-isoquinoline scaffolds which were smoothly elaborated to the targeted lamellarins alkaloids. The total synthesis of lamellarins Z and S with the highest overall yield reported till date, besides the synthesis of several other natural lamellarins have been realized in 5-6 steps with overall yields ranging from 20-27%.