Synthesis of 3-substituted isocoumarins via a cascade intramolecular Ullmann-type coupling-rearrangement process.

A simple and highly efficient strategy for the synthesis of 3-substituted isocoumarins through a copper(I)-catalyzed reaction of 1-(2-halophenyl)-1,3-diones has been developed. The procedure is based on a cascade copper-catalyzed intramolecular Ullmann-type C-arylation and rearrangement process. This methodology is tolerant of a wide range of substrates and applicable to library synthesis.