Meta-Selective Phenylselenylation of Pyridines through Oxazino Azines.

A metal-free and TCCA-promoted highly regioselective meta-C-H bond phenylselenylation of pyridines using bench-stable dearomatized oxazino azines has been developed. A substantial variety of 3-(phenylselanyl)pyridines were obtained under open-air and mild conditions, with a maximum yield of 90%. The scalable process was also available from pyridine directly in a "one-pot" version and was used in the late-stage meta-phenylselenylation of pyridine-containing drugs and natural product derivatives, providing an efficient platform for diverse meta-selective selenylfunctionalization of pyridine frameworks.