Pd-Catalyzed Asymmetric Cycloaddition Reaction Of Vinyl Three-Membered Ring Compounds With Compounds Containing Unsaturated Bonds

Palladium-catalyzed asymmetric[3+2]cycloaddition reaction of vinyl cyclopropane compounds with compounds containing unsaturated bonds is a very important strategy to prepare substituted five-membered ring compounds.The substrates containing carbon-carbon unsaturated bonds that can react with vinyl three-membered ring compounds are mainly electron-deficient olefins.However,the cycloaddition reaction of alkynes which also contain carbon-carbon unsaturated bonds with vinyl cyclopropane has not been reported.This thesis studied the Palladium-catalyzed asymmetric cycloaddition reaction of vinyl cyclopropane compounds with electron-deficient alkynes.We first have successfully realized the[3+2]cycloaddition reaction of alkynes with dicyano-substituted vinyl cyclopropane by regulating the electrophilic groups of the alkynes substrate and using alkynylα-keto ester as substrates.By using a catalyst derived from Pd（dba）₂ and（R）-SEGPHOS and performing the reaction in the mixture solvent consisting of dichloromethane and 1,2-dimethoxyethane in a proportion of 1.2:0.8 at 10°C,a variety of polysubstituted cyclopentene compounds were obtained in26-89%yields with 51-89%enantioselectivities.It is worth mentioning that this reaction has a wide scope of substrate.The substituents on alkynes can be aryl,hetero-aryl,alkyl,hetero-atomic substituents and so on.Furthermore,the reaction can also proceed smoothly when the ester group of alkynylα-ketone ester substrate is replaced by carbonyl group.