Polyglycerol as a high-loading support for boronic acids with application in solution-phase Suzuki cross-couplings

In this paper, we describe the usage of a soluble high-loading polyglycerol support for functionalized boronic acids without further linker design. The quantitatively formed polyglycerol boron esters were subsequently employed in homogeneous Suzuki cross-coupling reactions to give high yields (84-91%) of functional biaryls with minimal amounts of the Pd catalyst (0.2 mol %). In situ precipitation and ultrafiltration were used as simple and effective purification protocols. Furthermore, the reaction conditions were optimized by the choice of the solvent and the catalyst.