Pd(OAc)2-biuret: A highly efficient, low cost and phosphine-free catalyst system for biaryl synthesis under aerobic conditions at room temperature

Abstract

A highly efficient, less expensive and phosphine-free protocol for the Suzuki-Miyaura cross-coupling reactions of aryl halides and aryl boronic acids in iPrOH-H2O solvent under aerobic conditions has been developed. The results demonstrate that the biuret played a crucial role and making this protocol highly efficient. The Pd(OAc)2-biuret system exhibited superb catalytic activity towards the Suzuki-Miyaura cross-coupling reaction of a wide range of aryl halides with aryl boronic acids at room temperature, giving high yields even under very low catalytic loading. This system offers an attractive alternative to the existing protocols since the reaction proceeds in green solvent at room temperature with working simplicity, shorter reaction time, cost-effectiveness and provides the desired products in high yields. The effect of solvent, base as well as catalyst loading on the cross-coupling reaction of aryl halide with arylboronic acid is also described.