Recent advances in catalytica symmetric Buchner reaction

Bichner reaction,as a unique type of expansive dearomatization,has become a practical strategy for the straightforward assembly of valuable functionalized cycloheptatrienes from ubiquitous aromatic precursors.Although the asymmetric version has been investigated since the early 1990s,enantioselective Bichner reaction is still limited by the catalyst type and substrate scope.This review aims to propose the limitation and possible development direction of this field by summarizing the evolution of catalytic asymmetric Bichner reaction,which is organized on the basis of intra-and intermolecular reactions.Considering the different metal carbene precursors,the reactions are further classified by carbene sources.