Tandem radical reactions of isonitriles with 2-pyridonyl and other aryl radicals: Scope and limitations, and a first generation synthesis of (+/-)-camptothecin

Photolysis of N-propargyl-6-halo-2-pyridones and related aromatic halides in the presence of aryl isonitriles provides tetra- and pentacyclic products in a single step by a sequence of radical addition to the isonitrile followed by two cyclizations. The scope and limitations of the process are described along with a first generation synthesis of racemic camptothecin. Copyright (C) 1996 Elsevier Science Ltd