A Metal-Free Addition/Dearomatization–Cyclization/Decarboxylation Cascade Of Aryl3-Arylpropiolate Toward The Synthesis Of 1,1-Diaryl-2-Alkyl-Substituted Ethylenes

This thesis is divided into two parts:the first part are reviews about the synthesis of trisubstitutedalkenes which are classified according to Name Reactions.Researching progress on the synthesis methodology of novel reaction substrate is described in the second part of this thesis.The reaction mechanism,the synthetic process and the influence factors were discussed.The synthesis of trisubstitutedalkenes is an evergreen topic in the field of synthetic chemistry as these types of structural moieties broadly exist in a number of bioactive molecules and important synthetic intermediates such as Sunitinib,Oseltamivir,Isotretinoin,Rapamycin,and Epothilones.A radical-participated addition/dearomatization–cyclization/decarboxylation cascade between aryl3-arylpropiolate and ethers(cycloalkane)has been developed to give a series of 1,1,2-trisubstitutedethylenes in moderate to good yields.The reaction should be initiated by the thermal homolysis of BPO to give an oxygen-centered radical,which reacted with 1,4-dioxane to afford radical intermediate II through a hydrogen abstraction process.The addition of II to the carbon–carbon triple bond led to the vinyl radical intermediate III,which would produce spirointermediate IV through an intramolecular dearomatization–cyclization.Next,the aromatization/C–O bond cleavage would afford the carboxyl radical intermediate V,which underwent a decarboxylation to form vinyl radical VI.Finally,another hydrogen abstraction of 1,4-dioxaneby intermediate VI would give the product.