Ppm Level Supported Pd-catalyzed Carbonylative Suzuki–Miyaura Cross-Coupling of Aryl Iodides Using Oxalic Acid As CO Source

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. similar to 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.