Beneficial effect of cesium salts on Pd-catalyzed hydroxycarbonylation

A Pd(0)-catalyzed hydroxycarbonylation of the aryl bromide was effectively carried out in the presence of some Cs salts such as cesium carbonate, cesium bicarbonate, and cesium acetate in wet DMF solution. For the understanding of their function, an oxy-coordinated intermediate arising from a Cs–oxygen–Pd interaction has been postulated, which is likely to be responsible for related Cs assisted catalytic processes.