Synthesis Of NHC Carbene Catalyst Based On Cyclodextrin Cavity And UiO-68 Material And Its Application In Chlorination

Chlorine-containing organic compounds are not only an important class of chemicals,but also important raw materials for the synthesis of intermediates,natural products and functional materials.Traditio nally,organic chlorides are obtained by functional group transformation of olefins,alcohols,acids,etc.However,the direct introduction of chlorine atoms at the C-H bond is an efficient and straightforward approach to prepare these valuable compounds.For example,the common HLF reaction can achieve selective C(sp~3)-H chlorination.For the previous C(sp~3)-H chlorination reaction,high-purity organic solvents and free-radical stabilizers are req uired.the free radical stabilizers without,the reaction cannot proceed smoothly.In response to this situation,in this paper,two different types of NHC functionalized catalysts were synthesized using cyclodextrin and metal-organic frameworks(MOFs)as supports and used for photo-induced site-selective aliphatic C(sp~3)-H chlorination.The reaction is expected to proceed smoothly in an aqueous solvent and without a free radical-stabilizers.The main research contents are as follows:Topic 1:The imidazol ium salt was capped into the inner cavity of?-cyclodextrin through the benzylation,hydroxylation,mesylate and imidazole functionalization of?-cyclodextrin in turn to obtain?-cyclodextrin carbene catalyst and its use in the selective chlorination of amides and sulfonamides.Compared with the traditio nal NHC catalyzed chlorination reaction migration reaction,the innovation of this research method is:1)The migration reaction can be carried out smoothly without adding a free radical stabilizer;2)The m ixed solvent of H₂O and DCE is used for the reaction solvent.The volume of organic solvents is reduced;3)The cavity advantage of?-cyclodextrin carbene is prominently utilized,and the cyclodextrin cavity is used to further promote the chlorination reaction.Topic 2:Ui O-68-NHC MOF was synthesized by using Ui O-68 MOF as a carrier to load free NHC into the framework of Ui O-68 by ligand exchange method.BET,SEM and PXRD data show that the structure of the Ui O-68 support after ligand exchange has not chang ed,and has good thermal stability and acid stability,and its pore size is about 4 nm.The innovations of this research method are:1)Synthesis of a new stable NHC-containing MOF material and its use in the selective chlorination of amides and sulfonamid es;2)Based on the reaction solvent conditions explored in this project,The solvent of the subject catalysis experiment selects pure water as the reaction solvent,and obtains a good yield;3)The catalyst Ui O-68-NHC can be reused for many times,and its catalytic activity is still good.