Study On The Asymmetric [3+2] Cycloaddition Reaction Of 1-styrylnaphthol With P-benzoquinone Catalyzed By Chiral Phosphoric Acid

Ortho-Quinone Methides(o-QMs)intermediate is one of the important intermediates in organic synthesis.Which can participate in many reactions,such as Michael addition,[4+n] cycloaddition and Prins cyclization reaction.In recent years,asymmetric synthesis via o-QMs intermediate has become a hot topic in organic chemistry.This thesis is divided into three main parts,the first part summarizes the progress of catalytic asymmetric reactions with o-QMs intermediates in various catalytic systems,including transition metals,Br?nsted acids,N-heterocyclic carbenes,phase-transfer catalysts catalyzed reactions.In the second part,we have successfully discolsed an enantioselective catalytic [3+2] cycloaddition to construct a class of 2,3-diarylbenzofuran skeletons by chiral phosphoric acid catalyzed coupling reactions of 1-styrylnaphthols and 1,4-quinones.After optimization of the reaction conditions systematically by varying different substituents of catalysts,solvents,reaction time and concentration,we obtained the optimal reaction conditions.A series of different substrates of 1-styrylnaphthols and quinones have been explored under the optimal reaction conditions separately.A broad range of 1-styrylnaphthols and quinones can construct 2,3-diarylbenzofuran with two consecutive stereocentres were prepared(up to 99% yield,99% ee,dr>20:1).Additionally,catalyst loadings were also investigated.In the end,the reasonable mechanism to explain the process of this reaction was proposed.The method provides a new feasible way for the synthesis of drug molecules and natural products with chiral 2,3-diarylbenzofuran structure units.In the third part,Br?nsted acids catalyzed asymmetric oxa-Pictet-Spengler reaction were studied,no postive results were obtained at this moment.Futher investagations on this reaction is underway in our latoratory.