Axial Chiral Construction Of Furan Substituted Aryl Olefins Catalyzed By Asymmetric Binary Acids

Axial chiral compounds widely exist in bioactive molecules and natural products.Their synthesis and application have been greatly developed in the past few decades,and have been widely used in organic catalysts,metal ligands,chiral materials,and other fields.Compared to the vigorous development of research and application of biaryl axial chiral compounds in various fields,the development of axial chiral aryl alkenes has lagged behind for a long time in the past due to their high flexibility and poor stability of their chiral axes.However,the synthesis of open chain axis chiral olefins is more difficult due to the need to control the spin inhibition selectivity while regulating the Z/E selectivity of the product.Therefore,developing new synthesis strategies for these compounds has important research value.Vinylidene ortho-quinone methide（VQM）is a compound with multiple reaction sites and high reactivity that has been developed in recent years.It usually exists in the form of active intermediates in reactions,and is often used in the synthesis of axial chiral compounds.In this thesis,[4+2]cycloaddition reactions and Friedel-Crafts addition reactions have been achieved through VQM intermediates,respectively,and the construction of axially chiral open chain olefins has been completed.1)We have developed a chemically selective divergent coupling reaction of ortho-alkynylnaphthols with various benzofurans.The reaction was carried out through two different routes:under the catalysis of N-trifluoromethylphosphorimide,a chemically selective[4+2]cycloaddition process was achieved through activated VQM intermediates;Friedel-Crafts addition reaction was achieved by the formation of vinyl carbocation under the catalysis of binary-acid Sc（OTf）₃/diphenyl phosphate.In addition,we also found that diacid catalysts can also promote the ring opening reaction of axially chiral[4+2]cycloaddition compounds,resulting in axially chiral Friedel-Crafts addition products with corresponding chiral retention.2)We have developed a chiral N-trifluoromethylphosphoimide-catalyzed Friedel-Crafts addition reaction of ortho-alkynylnaphthols with[1,2-b]naphthofuran to synthesize a series of axially chiral aromatic olefins substituted with naphthofuran in excellent yields and enantioselectivity.