A Novel Methodology for Efficient Removal of Residual Palladium from a Product of the Suzuki−Miyaura Coupling with Polymer-Supported Ethylenediamine Derivatives

In our investigation to efficiently remove residual palladium from a drug candidate prepared via the Suzuki−Miyaura coupling reaction, it was found that polymer-bound ethylenediamines can absorb both Pd(0) and Pd(II). This property was applied to the removal of residual palladium from the crude 2‘-cyanobiphenyl product ( R )-2 obtained by the Suzuki−Miyaura coupling of an optically active bromobenzene derivative ( R )-1 with a boronate 3 . Treatment with the polymer-bound ethylenediamines reduced the palladium content of the crude product from 2000−3000 to 100−300 ppm. Subsequent purification by salt formation with di- p -toluoyl- d -tartaric acid (DTTA) attained a low palladium content of less than 10 ppm.