Selective synthesis of benzo[a]carbazoles and indolo[2,1-a]isoquinolines via Rh(Ⅲ)-catalyzed C-H functionalizations of 2-arylindoles with sulfoxonium ylides

【作者】 陈光； 贾瑞雪； 李彬； 范学森；

【Author】 Guang Chen;Ruixue Jia;Bin Li;Xuesen Fan;School of Chemistry and Chemical Engineering,Henan Normal University;

【机构】 河南师范大学化学化工学院；

【摘要】 A highly chem-and regioselective synthesis of diversely substituted benzo[a]carbazoles and indolo[2,1-a]isoquinolines through Rh(III)-catalyzed cascade reactions of 2-arylindoles with sulfoxonium ylides was established. To be specific, treatment of 2-arylindoles, 2-arylindole-3-carbaldehydes, 2-arylindole-3-carbonitriles or 2-aryl-3-methylindoles with sulfoxonium ylides under the catalysis of Rh(III) led to the selective formation of 6-aryl/alkylbenzo[a]carbazoles, 5-acylbenzo[a]carbazoles, 6-amino-5-acylbenzo[a]carbazoles or 12-methylindolo[2,1-a]isoquinolines, respectively. Mechanistically, the formation of the title compounds is believed to involve a cascade process including metallation of the inert C(sp2)-H bond, migratory insertion of ylide into the carbon–metal bond via an in situ carbenoid formation, protodemetalation, and intramolecular condensation. To our knowledge, this is the first example in which β-carbonyl sulfoxonium ylides were used as stable carbene precursors and bifunctional C2 synthons to form benzo[a]carbazoles and indolo[2,1-a]isoquinolines.更多还原

【Abstract】 A highly chem-and regioselective synthesis of diversely substituted benzo[a]carbazoles and indolo[2,1-a]isoquinolines through Rh(III)-catalyzed cascade reactions of 2-arylindoles with sulfoxonium ylides was established. To be specific, treatment of 2-arylindoles, 2-arylindole-3-carbaldehydes, 2-arylindole-3-carbonitriles or 2-aryl-3-methylindoles with sulfoxonium ylides under the catalysis of Rh(III) led to the selective formation of 6-aryl/alkylbenzo[a]carbazoles, 5-acylbenzo[a]carbazoles, 6-amino-5-acylbenzo[a]carbazoles or 12-methylindolo[2,1-a]isoquinolines, respectively. Mechanistically, the formation of the title compounds is believed to involve a cascade process including metallation of the inert C(sp2)-H bond, migratory insertion of ylide into the carbon–metal bond via an in situ carbenoid formation, protodemetalation, and intramolecular condensation. To our knowledge, this is the first example in which β-carbonyl sulfoxonium ylides were used as stable carbene precursors and bifunctional C2 synthons to form benzo[a]carbazoles and indolo[2,1-a]isoquinolines.更多还原