Improved Preparation of 4,6,6-Trimethyl-1,3,2-dioxaborinane and Its Use in a Simple [PdCl2(TPP)2]-Catalyzed Borylation of Aryl Bromides and Iodides



We describe a convenient preparation of 4,6,6-trimethyl-1,3,2-dioxaborinane (MethylPentaneDiolBorane, MPBH) and demonstrate that it is an excellent reagent for the [PdCl2(PPh3)2]-catalyzed borylation of aryl bromides and iodides. The corresponding boronic esters undergo rapid Suzuki coupling reactions in the presence of cesium fluoride. Thus, MPBH is an excellent alternative to pinacolborane for Pd-catalyzed borylation and cross-coupling reactions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)