Copper-catalyzed tandem annulation of 2-alkynoyl-2′-iodo-1,1′-biphenyls with isocyanoacetates: a rapid access to pyrrole-fused tetracyclic skeletons

An efficient and convenient synthesis of pyrrole-fused tetracyclic skeletons is presented. In this protocol using CuI as a catalyst, 1,1 '-biphenyl substrates with 2-alkynoyl and 2 '-iodo groups react with isocyanoacetates to provide 7-membered cyclic ketones fused with pyrrole and biphenyl rings through tandem [3 + 2] cycloaddition and C-C coupling processes.