Visible Light-promoted Reductive Decarboxylation/heteroaryl Migration/remote Cyanation Reaction And Its Synthetic Applications

Due to their low cost,easy availability,suitable chemical reactivity,and good stability,carboxylic acids and their derivatives are frequently usedas important feedstocks in organic synthesis.Cyano group(-CN),as a class of significant functional groups,is a ubiquitous structural unit in various biologically and medicinally active molecules.Furthermore,nitriles can be readily converted to other types of compounds such as amines,N-heterocycles,amides,and carboxylic acid derivatives.In recent years,the decarboxylation of visible light-induced carboxylic acids and their derivatives has gradually been developed as an effective strategy for obtaining carbon-centered radical intermediates,and has become one of the activeresearch fields.Recently,radical-triggered group migration reactions have also attracted great attention from chemists.To date,radical-mediated group migration reactions,including cyano,aryl,formyl,alkenyl,alkynyl,and heteroaryl,have been reported by several research groups.However,the substrates employed in such migration reactions are restricted to hydroxyl-containing compounds that generally require multiple synthetic steps and thus are difficult to be prepared.Morever,these reported migration reactions can only afford the corresponding ketones,which greatly limits the diversity and structural complex of products and synthetic applications of such methods.In this thesis,a highly efficient reductive decarboxylation/heteroaryl migration/remote cyanation reaction has been achieved with N-(acyloxy)phthalimide derivatives as substrates,TMSCN as the cyano source,and the combination of visible-light photoredox catalysis and group migration strategy,thus giving the novel cyano-featured heterocycles in excellent chemo-and regioselectivities.The optimized reaction conditions were established by sreening catalysts,additives,and solvents.The optimized product yield can be obtained by treating N-(acyloxy)phthalimide dervatives and TMSCN in the presence of Eosin Y,CuBr,and i-Pr2NEt in DMF at ambient temperature for 36 h under irradiation with a 23 W CFL.With the optimal conditions in hand,we next investigated the substrate scopes.The corresponding products were obtained in good yields and characterized by using1H NMR,13C NMR,and HRMS.All 20 synthetic products are new compounds and have not been reported before.To further demonstrate the potential synthetic applications,we performed the related chemical transformation for products.For example,the product can be easily converted into the tetrazole compound in a reasonable yield with TMSN3 as nitrogen source.Based on the experimental results and the previous reports,a plausible reaction mechanism was also proposed.