| Tris（pentafluorophenyl）borane,which is a strong Lewis acid catalyst,has attracted significant attention from chemists worldwide.Over the past twenty years,with the rapid development of organic boron chemistry,many new catalytic reactions have been explored and important advancements have been made.Due to its unique structure,tris（pentafluorophenyl）borane is widely used as Lewis acid catalyst.However,the potential of tris（pentafluorophenyl）borane hydrate（B（C6F5）3·H2O）has not been fully investigated.There are several challenges that need to be tackled:（1）It is hard to indentify real catalytic species under moist conditions,due to the coordination between B（C6F5）3 and water is competitive.（2）The crystals formed by B（C6F5）3·H2O and organic molecules are rarely obtained,because the activation of organic molecules by B（C6F5）3·H2O is generally carried out via non-covalent interaction which is highly reversible.（3）The lack of efficient methods for regulation of the activity of B（C6F5）3·H2O.This dissertation focuses mainly on studying the non-covalent interaction between B（C6F5）3·H2O and small molecules,the mechanism is investigated by using X-ray crystal structure analysis,nuclear magnetic resonance,UV-Vis spectrophotometry,as well as developing B（C6F5）3·H2O catalyzed reactions.The research works are listed as follows:（1）A visible light-driven aerobic oxidation reaction catalyzed by B（C6F5）3·H2O has been developed.This reaction efficiently generates a series ofα-aminoamides from tetrahydroisoquinoline derivatives,isocyanides,and water,exhibiting good functional group tolerance under mild reaction conditions.The protocol can be applied to synthesize drug derivatives,such as Bupivacaine.The crystal structure,formed by B（C6F5）3·H2O and amide derivative,was analyzed using X-ray crystal structure analysis,which revealed that B（C6F5）3·H2O can facilitate the amide derivative to exhibit visible light absorption properties through intermolecular hydrogen bonding andπ-πinteractions.Characteristic properties of the complex of B（C6F5）3·H2O and amide in the solution are also investigated by UV-Vis spectrophotometry,fluorescence emission spectroscopy,and electron paramagnetic resonance.（2）A direct nucleophilic substitution reaction of benzyl fluorides was developed,catalyzed by B（C6F5）3·H2O,using alcohol as a nucleophilic reagent.This reaction features a wide range of nucleophilic reagents without pre-activation or pre-functionalization and simple operation.Defluorination of benzyl fluoride derivatives was realized by using cooperative catalysis of B（C6F5）3·H2O and tetrahydrofuran,suppressing the Friedel-Crafts reaction of benzyl fluorides while selectively obtaining the nucleophilic substitution products.Moreover,the unique hydrogen bond between B（C6F5）3·H2O and alcohol was observed,enhancing the nucleophilicity of alcohol and providing a new strategy for nucleophilic substitution reactions of alcohol under acidic conditions.（3）An alkylation reaction of sulfonamides was developed using ketone and tertiary alcohol as alkylation reagent in the presence of B（C6F5）3·H2O and silane.B（C6F5）3·H2O acts as hydrogen bond acceptor to form hydrogen bond with sulfonamide,which enhances the nuclophilicity of weak nucleophile sulfonamide,and achieving alkylation of sulfonamides by various ketone derivatives,while suppressing the elimination reaction of tertiary alcohol under Br?nsted acid condition.This work provides a novel pathway for the alkylation reaction of sulfonamides and expanded the application of B（C6F5）3·H2O in nucleophilic activation.This dissertaation mainly investigated the non-covalent interactions between tris（pentafluorophenyl）borane hydrate and small molecules,revealing the impact of intermolecular hydrogen bonding andπ-πinteractions on the catalytic process of tris（pentafluorophenyl）borane hydrate.These findings provide new insights into the unique catalytic properties of B（C6F5）3·H2O.Moreover,a series of simple and mild transformation reactions have been developed,expanding its application range in catalytic conversions,and providing theoretical guide for the development of novel Br?nsted acid catalytic systems. |
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