Generation of 4-iodoisocoumarins through a TBAI-mediated oxidative cyclization of 2-alkynoates

A tetra-butylammonium iodide (TBAI)-mediated oxidative iodocyclization of 2-alkynoates for the synthesis of various 4-iodoisocoumarin is described herein, and the reaction is highly efficient and shows broad functional group tolerance. This newly developed reaction uses a mixture of water and DCE as co-solvent, and avoids the use of iodine as iodine source for the electrophilic halocyclization.