Highly Selective Synthesis Of Indole-containing Tetracyclic Compounds

In this thesis,several highly efficient and novel methodologies for the preparation of indole-containing tetracyclic compounds(such as: indolo[1,2-c]quinazolines,11H-indolo[3,2-c]quinolines,6H-isoindolo[2,1-a]indol-6-ones and indeno[1,2-b]indol-10(5H)-ones)have been successfully developed through copper/palladium-catalyzed cascade reactions of 2-(2-bromoaryl)-1H-indoles with different reaction partners.The main research results are as follows:Firstly,highly regioselective synthesis of indolo[1,2-c]quinazolines and 11H-indolo[3,2-c]quinolines through copper-catalyzed one-pot two-step three-component cascade reaction of 2-(2-bromoaryl)-1H-indoles with aldehydes and aqueous ammonia has been successfully realized by simply tuning the pH value of the reaction system.The reaction results indicated that under nitrogen atmosphere,the copper-catalyzed cascade reaction of 2-(2-bromoaryl)-1H-indoles with aldehydes and aqueous ammonia can firstly afford 5,6-dihydroindolo[1,2-c]quinazolines as key intermediates,and then heating the reaction mixture under air could give rise to indolo[1,2-c]quinazolines in a highly regioselective manner;whereas adjusting the pH value of the reaction system to a range of 5-6 followed by heating the resulting mixture under air could regioselectively afford 11H-indolo [3,2-c]quinolines.Secondly,we have also developed a highly selective and new method for the preparation of 6H-isoindolo[2,1-a]indol-6-ones and indeno[1,2-b]indol-10(5H)-ones via palladium-catalyzed cyclocarbonylation reaction of 2-(2-bromoaryl)-indoles with CO as C1 source.Notably,the regioselectivity can be easily controlled by employing different substrates.With 2-(2-bromoaryl)-1H-indoles as reactants,this reaction could regioselectively afford 6H-isoindolo[2,1-a]indol-6-ones,whereas indeno[1,2-b]indol-10(5H)-ones could be obtained in a highly selective manner by using N-substituted 2-(2-bromoaryl)-1H-indoles as substrates.