Remote Meta-C–H Activation Using a Pyridine-Based Template: Achieving Site-Selectivity via the Recognition of Distance and Geometry
journal contributionposted on 17.12.2015 by Ling Chu, Ming Shang, Keita Tanaka, Qinghao Chen, Natalya Pissarnitski, Eric Streckfuss, Jin-Quan Yu
Any type of content formally published in an academic journal, usually following a peer-review process.
The pyridyl group has been extensively employed to direct transition-metal-catalyzed C–H activation reactions in the past half-century. The typical cyclic transition states involved in these cyclometalation processes have only enabled the activation of ortho-C–H bonds. Here, we report that pyridine is adapted to direct meta-C–H activation of benzyl and phenyl ethyl alcohols through engineering the distance and geometry of a directing template. This template takes advantage of a stronger σ-coordinating pyridine to recruit Pd catalysts to the desired site for functionalization. The U-shaped structure accommodates the otherwise highly strained cyclophane-like transition state. This development illustrates the potential of achieving site selectivity in C–H activation via the recognition of distal and geometric relationship between existing functional groups and multiple C–H bonds in organic molecules.