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

The
potential advantages of using arylboronic esters as boron sources
in C–H borylation are discussed. The concept is showcased using
commercially available 2-mercaptopyridine as a metal-free catalyst
for the transfer borylation of heteroarenes using arylboronates as
borylation agents. The catalysis shows a unique functional group tolerance among C–H borylation reactions,
tolerating notably terminal alkene and alkyne functional groups. The
mechanistic investigation is also described.