Copper-Catalyzed Defluorinative Arylborylation Of Alkenes With Polyfluoroarenes

Polyfluoroarenes are widely present in pharmaceutical molecules,organic materials and agricultural chemicals,and their excellent properties have attracted extensive attention in the past decades;accordingly,a number of methods have been developed to realize its efficient synthesis.Among them,it is one of the most convenient and efficient ways to synthesize polyfluoroarenes derivatives using bulk and cheap polyfluoroarenes as substrates through C–F bond functionalization.However,due to the smaller radius of fluorine atom,C–F bond has shorter bond length and larger bond energy than other C–X(X=Cl,Br)bonds,the C–F bond activation of fluorine arene has to overcome its own chemical infertility;moreover,polyfluoroarenes may contain many different C–F bonds,and how to achieve site-selective C–F bond activation is another difficult challenge in this field.Nevertheless,the use of stoichiometric organometallic reagents(e.g.,organolithium/magnesium/zinc reagents)for nucleophilic to realize C–F bond alkylation with polyfluoroarenes by nucleophilic substitution has been reported;highly active organometallic reagents have the disadvantages of poor functional group compatibility,harsh reaction conditions,sensitive to water and air,and not easy to store,which seriously limit their wide application.Therefore,it is of great theoretical and practical value to develop new methods to avoid the above defects undoubtedly.On the other hand,boron-containing compounds are one of the most important intermediates in modern organic synthesis because of their excellent functional group compatibility,low toxicity,insensitivity to air and water and excellent functional group conversion ability.Among a large number of developed methods for the synthesis of boron-containing compounds,the boration functionalization reactions of unsaturated hydrocarbons have attracted great attention.Nevertheless,the boration/defluorinative arylation of unsaturated hydrocarbons has not been reported.Based on the important applications of polyfluoroarenes and organoborate compounds in many fields,it is of great research value to develop novel and efficient new methods for the synthesis of boron-containing polyfluoroarenes derivatives,avoiding the limitations of the existing methods.In this paper,a series of boron-containing polyfluoroarenes were obtained with good yield and high regional selectivity by the defluorinative arylboration reaction between alkenes and polyfluoroarenes by using cheap metal copper salt as catalyst.The reaction conditions were mild,with good functional group compatibility and relatively broad range of substrate(monosubstituted alkenes,1,1-disubstituted alkenes,1,2-disubstituted alkenes can all effectively participate in the reaction),and this conversion can be used to synthesize challenging boron-containing polyfluoroarenes with quaternary carbon center.This strategy provided a new idea for the selective C–F bond functionalization of polyfluoroarenes under mild conditions to generate a series of important boron-containing polyfluoroarenes derivatives.