Iridium-Catalyzed Site- and Enantioselective C(sp2)-H Borylation of
Benzhydryl Ethers: Enantioselectivity Amplification by Kinetic
Resolution Relay
Abstract
We herein report a simple ether-directed iridium-catalyzed site- and
enantioselective C(sp2)-H borylation of benzhydryl ethers for the first
time. Various chiral benzhydryl ethers were obtained with high
enantioselectivities in the presence of a tailor-made chiral bi-dentate
boryl ligand. We found that the kinetic resolution relay significantly
amplified the enantioselectivity. The synthetic utility of the current
method was demonstrated by gram-scale C-H borylation and C-B bond
transformations.