Access to Enantioenriched Benzylic 1,1-Silylboronate Esters by Palladium-Catalyzed Enantiotopic-Group Selective Suzuki-Miyaura Coupling of (Diborylmethyl)silanes with Aryl Iodides

This work describes the palladium-catalyzed enantiotopic-group selective Suzuki-Miyaura cross-coupling of (diborylmethyl)silanes with aryl iodides. The combination of a Pd(TFA)(2) and rev-Josiphos-type ligand bearing a 3,5-bis(trifluoromethyl)phenyl as benzylic phosphine substituent in the presence of NaI as an additive and NaOMe as a base promotes the reaction to high efficiency and enantioselectivity. This method provides a convenient approach for synthesizing chiral benzylic 1,1-silylboronate esters from readily accessible reagents. Synthetic applications including stereospecific C-O, C-N, and C-C bond-forming reactions of boron group are also demonstrated.