Study On The Synthesis Of Benzo-condensed Heterocyclic Compounds Based On Palladium-Catalyzed Tandem Reactions

Heterocyclic compounds have found widespread existence in natural products and drugs,so it is of great importance to develop concise,highly efficient and facile methods to synthesize these compounds.Tandem reaction,which is an atom economic reaction with advantages mentioned above,provide a powerful tool for their synthesis.In the dissertation,the benzo-condensed heterocyclic compounds were synthesized via palladium-catalyzed intermolecular Heck coupling/intramolecular allylation based on(Z)-ethyl 2-(phenoxy(phenyl)methyl)but-2-enoate which was the product of phosphine-catalyzed umploung addition of allenoates.Firstly,twenty-seven indoline derivatives were synthesized in using palladium-catalyzed tandem Heck coupling/allylation between N-(2-iodophenyl)-4-methylbenzenesulfonamide and(Z)-ethyl2-(phenoxy(phenyl)methyl)but-2-enoate,which yield was 28%-81%.By screening of reaction parameters such as temperature,solvent,base,catalyst and so on,the highest yield was obtained employing Pd(dppe)Cl2 as the catalyst,NaHCO3 as the base,n-Bu4 NCl as the additive and DMF as the solvent at 130 oC for 12 h.The diene intermediate was formed by the hydrogen-extraction elimination of(Z)-ethyl2-(phenoxy(phenyl)methyl)but-2-enoate.Twenty-seven target products were synthesized via palladium-catalyzed intermolecular Heck coupling/intramolecular allylation between the diene intermediate and N-(2-iodophenyl)-4-methylbenzenesulfonamide,which were characterized by 1H NMR,13 C NMR,IR and HRMS.Secondly,isochroman derivatives were synthesized via Palladium-catalyzed tandem Heck coupling/allylation between(2-iodophenyl)methanol and(Z)-ethyl-2-(phenoxy(phenyl)methyl)but-2-enoate.The diene intermediate was formed by the hydrogen-extraction elimination of(Z)-ethyl2-(phenoxy(phenyl)methyl)but-2-enoate.(E)-ethyl-2-(isochroman-3-yl)-3-phenylacrylate was synthesized via palladium-catalyzed intermolecular Heck coupling/intramolecular allylation between the diene intermediate and(2-iodophenyl)methanol,which were characterized by 1H NMR,13 C NMR and IR.No more than 25% yield of(E)-ethyl-2-(isochroman-3-yl)-3-phenylacrylate was obtained through the screening of temperature,solvent,base,catalyst and so on.This work was underway in our labratroy.