Chiral Phosphoric Acid-Catalyzed Remote Control of Axial Chirality at Boron–Carbon Bond
Junxian Yang, Jiwei Zhang, Jiwei Zhang, Wen Bao, Sheng‐Qi Qiu, Shaoyu Li, Shao‐Hua Xiang, Jun Song, Junmin Zhang, Junmin Zhang, Bin Tan
Abstract
The previously elusive catalytic enantioselective construction of axially chiral B-aryl-1,2-azaborines with a C-B stereogenic axis has been realized through a chiral phosphoric acid-catalyzed desymmetrization strategy reported herein. The electrophilic aromatic substitution reaction of 3,5-disubsituted phenols with diazodicarboxamides could afford these axially chiral structures in good efficiency with excellent enantiocontrol. The efficient long-range stereochemical control is achieved by multiple well-defined H-bonding interactions between chiral phosphoric acid and both substrates. Meanwhile, the reaction duration could be markedly shortened with weakly acidic N-H in 1,2-azaborine acting as H-bond donor. The scalability of the reaction and facile cleavage of the N-N bond in the product further demonstrated the practicality of this method.