Isodesmic C-H Borylation: Perspectives and Proof of Concept of Transfer Borylation Catalysis

The potential advantages of using arylboronic acidsor esters as boron source in the C-H borylation are discussed. Theconcept is showcased by using commercially available and air-stable2-mercaptopyridine as a metal-free catalyst for the transferborylation of heteroarenes, using furylboronic acid catechol esteras the borylation agent. The catalysis can be performed in air usingunpurified solvent and shows a unique functional group toleranceamong C-H borylation reactions, tolerating notably alkene and alkynefunctional groups. The computational investigation of themechanism is also described.