Rh(Ⅲ)-Catalyzed C-H Bond Naphthylation And Cascade Directing Group Transformation To Access Naphthalene-Substituted Aromatic Esters

Rh-catalyzed direct aromatic C-H bond functionalization,due to its excellent atomic economy,broad substrate scope,reaction selectivity,and high efficiency,has been a powerful tool for synthesizing substituted aromatics.As a fundamental condensed aromatic,naphthalene is frequently found in drug molecules,agrochemicals,and organic luminescent materials.As such,the synthesis of naphthalene-substituted aromatics has attracted more and more attention in the past decades.Among numerous synthetic methods for constructing naphthalene-substituted aromatics,direct naphthalylation of aromatic C-H bonds dominated reaction simplicity.It could deliver the naphthalene-substituted aromatics efficiently.However,the reported methods for direct naphthalylation of aromatic C-H bonds still face challenges regarding reaction efficiency and selectivity.In this thesis,based on the intensive research of Rh-catalyzed C-H bond functionalization,we have developed a new method for synthesizing naphthalene-substituted aromatic esters via Rh（III）-catalyzed C-H bond naphthylation and cascade directing group transformation.A series of naphthalene-substituted aromatic esters were produced efficiently and selectively.The model reaction was successfully conducted on a gram scale.Benefitting from the acquisition of the ester group,post-derivatization was performed effectively.Additionally,the mechanism of this catalytic reaction was proposed.The above works are summarized as follows:Firstly,a new method for synthesizing naphthalene-substituted aromatic esters via Rh-catalyzed C-H bond naphthalylation and cascade directing group transformation was developed.In this protocol,[Cp*Rh Cl₂]₂/Ag Sb F₆ was employed as the catalyst,diverse aryl imidates were used as the substrates,and oxa bicyclic alkenes were chosen as the naphthalene source.Various ortho naphthalene-substituted aromatic esters were obtained selectively and efficiently under mild reaction conditions.Secondly,owing to the precise transformation of directing group,the carboxy group could be served as the following C-H bond functionalization.And several derivatization products were synthesized easily.Based on the excellent catalytic activity of this approach,the model reaction can be efficiently scaled-up.Finally,an ¹⁸O labeling experiment and several control experiments were conducted to investigate the source of carbonyl oxygen.H/D scrambling experiments and determining e kinetic isotope effect（KIE）value were performed to search the turnover-limiting step in this catalytic cycle.Based on the above results and previous works,a possible mechanism for this reaction and the source of the carbonyl oxygen were proposed.