Asymmetric Friedel-Crafts Arylation Reaction Of 1-Azadienes Access To Chiral Heterotriarylmethanes

Asymmetric Friedel-Crafts(F-C)arylation reaction is one of the most powerful and versatile protocols for the synthesis of optically enriched aromatic compounds with the new C-C bond formation.In the last decades,the organocatalytic asymmetric F-C arylation of electronic-rich(hetero)arenes and electrophiles has achieved great progress,compared with metal catalysis.With the development of electrophiles in asymmetric FC reaction,?,?-unsaturated carbonyl compounds,nitroolefins,carbonyl compounds,imines and even the corresponding cation precursors have been well-studied.However,the utility of stable 1-azadienes in the organocatalytic asymmetric F-C arylation was still immature,probably owing to the readily decomposition and competitive nucleophilic 1,2-addition of 1-azadienes.1-Azadienes,each containing a structurally unique s-cis configuration of exocyclic alkylidene and imine residues on the benzofuran core,have drawn our attention.Base on it,this article is using 1-azadiene as electrophile to develop two reactions respectively: Asymmetric Friedel-Crafts arylation of 2-naphthols or sesamols catalyzed by bifunctional tertiary amine-urea catalysts;Asymmetric Friedel-Crafts heteroarylation of indoles catalyzed by chiral phosphoric acid catalysts.The methodology not only facilely enables the asymmetric synthesis of the privilege benzofuran-containing mono-,di-and trihetero-arylmethanes in up to 98% yield with up to 99% ee,but also enriched the development of catalytic asymmetric Friedel-Crafts reaction...