Study On The Construction Of Axially Chiral Biphenyl Aryl Nitrile Compounds Catalyzed By Nitrogen Heterocyclic Carben

Cyanide compounds are not only widely found in medicine and pesticide molecules,but also a class of important intermediates.The traditional method for the synthesis of cyano compounds is to use the simplest cyanide reagents such as sodium cyanide,potassium cyanide and hydrocyanic acid,but the toxicity and instability of cyanide reagents have limited its application in synthesis.Therefore,the development of cyanide-free reagents for the construction of cyano compounds has attracted much attention.Biocatalysis,metal catalysis and small-molecule organocatalysis have realized the construction of cyano compounds without cyanide-free reagents,but these catalytic modes mainly focus on the formation of central chiral cyano compounds.Axially chiral compounds are widely present in natural products and drug molecules.In addition,axially chiral compounds are widely used as ligands and organic catalysts for many reactions.In recent years,small-molecule organocatalysts has received considerable attention.N-Heterocyclic Carbenes catalysis(NHCs),as a rising star in the field of organic catalysis,can used for the umpolung(the inversion of polarity)of carbonyl compounds and achieved the rapid construction of various functional molecules.At present,a variety of catalytic activation modes have been developed to form various active intermediates,which are mainly used in the formations of carbon-carbon bonds and carbon-hetero bonds.However,there are relatively few studies on the construction of cyano compounds with cyanide-free reagents enabled by NHCs.Based on the previous work of our group in this field,we have expanded the application range for the construction of axially chiral biphenyl aromatic nitrile compounds with cyanide-free reagents enabled by NHCs.Biphenyldialdehyde derivatives bearing pro-chiral axis and readily available p-toluenesulfonamide are used as the reaction starting materials,with chiral NHC as the key organic catalyst.Axially chiral biphenyl aromatic nitriles bearing various substituents are afforded in good yields and excellent enantioselectivities.At the same time,the stereochemical stability of the axially chiral biphenyl aromatic nitriles is evaluated via thermal dynamic methods.Furthermore,various chemical transformations are performed on the products,leading to the synthesis of various chiral axis functional molecules in good yields with excellent enantioselectivities.