Electrosynthesis Enables Smiles Rearrangement And Enantioselective Benzylation

As an efficient and environmentally friendly green synthesis method,organic electrochemical synthesis has a long history and industrial application value.This method directly uses clean electrons as "reagents",avoiding the use of stoichiometric oxidants or reducing agents,which is in line with the important direction of green chemistry and sustainable development.Taking advantage of organic electrochemical synthesis,combining asymmetric catalytic synthesis with organic electrosynthesis to develop asymmetric electrocatalytic reactions will be an extremely efficient and green asymmetric synthesis strategy.This strategy can further expand the activation model,reaction type and substrate adaptability of asymmetric catalysis,and provide new ideas for organic electrochemical synthesis research.Our studies mainly focus on the construction of nitrogen-containing compounds by generating reactive N-center radicals under electrochemical action and the development of new types of electrochemical asymmetric synthesis reactions.Furthermore,the efficient rearrangement protocol has been reported to form the axial chiral aniline ligands for the development of electrochemical asymmetric synthesis.As an effective way to form N-center radicals by single electron transfer,electrochemical methods have been widely used in the construction of C-N bonds.The currently electrochemical methods for obtaining N-center radicals are mainly through the reaction pathway of anodizing N-H bonds of amine or amide compounds.In this thesis,an entirely new electrochemical reduction activation mode was developed to break the N-O bond to generate amidyl radicals,and a series of amide compounds were obtained with good to excellent yields through radical Smiles rearrangement.This strategy is also widely used in the synthesis of complex molecules and provides a new route for the synthesis of axial chiral aromatic amine compounds.Moreover,this method is the first to realize the strategy of C-N bond formation by Smile rearrangement reaction initiated by N-center radicals.Axial chiral biarylaniline derivatives are widely used as chiral ligands or chiral auxiliary agents in asymmetric synthesis.The use of highly efficient Smiles rearrangement to accomplish switchable enantioselective amination reactions of O-arenes gives access to non-symmetric 2'-amino-[1,l'-binaphthalen]-2-ol(i.e.,NOBIN-type)and[1,1'-binaphthalene]-2,2'-diamine(i.e.,BINAM-type)derivatives.This transition metal-free strategy provides a powerful way to access highly functionalized enantioenriched anilines.Using this methodology,structurally diverse axially chiral anilines can be produced in good yields with a broad scope,allowing the straightforward preparation of anilines from the corresponding aryl phenols.The process is a convenient,safe,and userfriendly method for large-scale preparation.The realization of chiral induction by asymmetric cascade electrochemical process is an important strategy for electrochemical asymmetric synthesis.An enantioselective detrifluoroacetylation alkylation reaction catalyzed by bifunctional squaramide under electrochemical conditions was developed.By merging electrosynthesis and asymmetric organicatalysis,this reaction achieves asymmetric synthesis of fluorine-containing target molecules with excellent enantioselectivity(up to 95%ee).In addition,this catalytic asymmetric detrifluoroacetylation alkylation reaction has also been applied in the preparation of biologically relevant products containing C-F bond ternary stereoisomeric centers.