Direct C–H Cyanation
Methods for the direct C–H functionalization of aromatic compounds are in demand for a variety of applications, including the synthesis of agrochemicals, pharmaceuticals, and materials. Published in the Journal of the American Chemical Society Herein, Joshua McManus and David Nicewicz disclose the construction of aromatic nitriles via direct C–H functionalization using an acridinium photoredox catalyst and trimethylsilyl cyanide under an aerobic atmosphere.
The reaction proceeds at room temperature under mild conditions and has proven to be compatible with a variety of electron-donating and -withdrawing groups, halogens, and nitrogen- and oxygen-containing heterocycles, as well as aromatic-containing pharmaceutical agents. The conditions developed are mild and proved to be compatible with sensitive or reactive functionalities. The reaction also avoids undesired reactivity at the benzylic positions of the substrates, allowing for exclusive aromatic ring C–H functionalization. Future studies are aimed at elucidating the origins of the regioselectivity in more complex substrates.