Palladium-Catalyzed Chemoselective Negishi Cross-Coupling of Bis[(pinacolato)boryl]methylzinc Halides with Aryl (Pseudo)Halides.

We describe a palladium-catalyzed chemoselective Negishi cross-coupling of a bis[(pinacolato)boryl]methylzinc halide with aryl (pseudo)halides. This reaction affords an array of benzylic 1,1-diboronate esters, which can serve as useful synthetic handles for further transformations. The developed coupling reaction is compatible with various functional groups and can be easily scaled up. The coupling of bis[(pinacolato)boryl]methylzinc halides with pharmaceuticals and the subsequent late-stage manipulations demonstrate the power of the developed protocol.