Synthesis of isochromenones and oxepines via Pd-catalyzed cascade cyclization of alkynes and benzynes involving C-H activation

A new method for the synthesis of various isochromen-6-ones and phenanthro[1,10-bc]oxepines via a palladium-catalyzed cascade carbocyclization of 2-iodobenzyl-3-phenylpropiolates and 1-iodo-2-(2-(phenylethynyl) benzyloxy) benzenes with arynes is described. The reactions involve interesting biscarbocyclization of alkynes and benzynes and C-H bond activation.