Oxygen-promoted PdCl₂-catalyzed ligand-free Suzuki reaction in aqueous media

Abstract

A simple and efficient protocol has been developed for the PdCl(2)-catalyzed ligand-free and aerobic Suzuki reaction of aryl bromides or nitrogen-based heteroaryl bromides with arylboronic acids in good to excellent yields in aqueous ethanol. A systematic investigation on the effect of different atmospheres on the reactivity of the palladium-catalyzed Suzuki reaction has been carried out, the results show that an aerobic atmosphere demonstrates a positive effect on the reactivity of the Suzuki reaction in an aqueous media and a negative effect in a pure organic solvent, which exhibits that the water plays a crucial role for the function of the atmosphere on the palladium-catalyzed ligand-free Suzuki reaction.

Speciation of Pd(OAc)2in ligandless Suzuki–Miyaura reactions

“…27,28 More recently, PdCl 2 can also be activated towards catalysis in an aqueous media under an aerobic atmosphere. 30 In these papers, the beneficial effects of O 2 and H 2 O were illustrated by the comparison of isolated yields, rather than kinetic profiles, and it was not clear how these promoters exert a beneficial effect for catalysis. In the present work, we will delineate the role of each of the reacting components in catalyst activation, stability and eventual deactivation.…”

Suzuki cross-coupling in aqueous media

“…10,11,[34][35][36][37] Ligand-free catalysts allow the reaction to occur in aqueous and aerobic media as well as under mild reaction conditions. Indeed, successful conversion of sterically hindered, or the less reactive aryl chlorides, is still a problem that is frequently studied.…”

Palladium immobilized in the nanocages of SBA-16: An efficient and recyclable catalyst for Suzuki coupling reaction

“…Solvents and base had remarkable influenced on the reactivity of the Suzuki reaction in reported earlier [44,45]. Now, we used ethanol as a medium for the Suzuki coupling because using ethanol as solvent represents a safe and cost-effective process.…”