Iridium-Catalyzed Borylation of Secondary C-H Bonds in Cyclic Ethers

The borylation of secondary C–H bonds, specifically secondary C–H bonds of cyclic ethers, with a catalyst generated from tetramethylphenanthroline and an iridium precursor is reported. This borylation occurs with unique selectivity for the C–H bonds located β to the oxygen atoms over the weaker C–H bonds located α to oxygen atoms. Mechanistic studies imply that the C–H bond cleavage occurs directly at the β position rather than at the α position followed by isomerization of a reaction intermediate. Read more on publisher's site.