N-Heterocyclic Carbene (NHC)-Catalyzed Desymmetrization of Biaryldialdehydes to Construct Axially Chiral Aldehydes

In the field of asymmetric catalytic synthesis, axially chiral aldehydes are often used as precursors of organic catalysts or chiral ligands because of their unique structures.The development of synthetic methods with enantioselectivity and structural diversity has always been the interest of chemists.However, only few catalytic methods have been developed for the construction of structurally diverse axially chiral aldehydes.Herein, a N-heterocyclic carbene (NHC)-catalyzed oxidative esterification reaction to synthesize axially chiral aldehydes through desymmetrization strategy was developed.This method features mild conditions (room temperature), excellent yields and enantioselectivity, broad substrate scope and good function group tolerance (26 examples, 54%～97% yields, up to 99% ee).All the axially chiral aldehyde products have been fully characterized and the absolute configuration was established by comparing the results from known literature.This strategy provides new possibilities for the synthesis of axially chiral aldehydes and their derivatives.