Ppm level supported Pd-catalyzed carbonylative Suzuki–Miyaura cross-coupling of aryl iodides using oxalic acid as CO source

Abstract

Polystyrene supported palladium (Pd@PS) catalyzed cost-efficient and sustainable protocol for carbonylative Suzuki-Miyaura cross-coupling (C-SMCC) reaction has been reported. Herein, ppm (parts per million) level of Pd (0.1 mol%, 1000 ppm) of the Pd@PS catalyst, with high turnover number, i.e. ∼5061 (calculated upto six cycles) was applied. Furthermore, to avoid the direct use of toxic, flammable, odorless carbon monoxide (CO) gas, oxalic acid has been applied as solid, inexpensive, additive-free CO source. The developed protocol is applicable to wide range of aryl iodides and phenylboronic acids that produce symmetrical and unsymmetrical biaryl ketones. Interestingly, di-carbonylative Suzuki-Miyaura cross-coupling products were also obtained in moderate to excellent yields.