title: Palladium-catalyzed annulation of allenes with indole-2-carboxylic acid derivatives: synthesis of indolo[2,3-c]pyrane-1-ones via Ar-I reactivity or C-H functionalization.
abstract: Two methodologies, one involving Ar-I reactivity and the other through C-H functionalization, for the formation of indolo[2,3-c]pyrane-1-ones via the corresponding allenes, are presented. A highly efficient approach to indolo[2,3-c]pyrane-1-one derivatives through the Pd-catalyzed regioselective annulation of allenes with 3-iodo-1-alkylindole-2-carboxylic acids is described. This method is fairly general for a wide range of allenes affording the respective indolo[2,3-c]pyrane-1-ones in good to excellent yields. In addition, a Pd(II)-catalyzed oxidative coupling of indole-2-caboxylic acid derivatives with allenes via direct C-H functionalization to afford the corresponding indolo[2,3-c]pyrane-1-ones in moderate to good yields has been developed.
authors: School of Chemistry, University of Hyderabad, Hyderabad 500 046, AP, India.
authors: R Rama
authors: RR
authors: Suresh
authors: K C Kumara
authors: KC
authors: Swamy
mesh_terms: D000466:Alkadienes / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D002264:Carboxylic Acids; D002384:Catalysis; D018360:Crystallography, X-Ray; D006859:Hydrogen / Q000737:chemistry; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*
chemical_list: D000466:Alkadienes; D002264:Carboxylic Acids; D007211:Indoles; C058980:indole-2-carboxylic acid; D010165:Palladium; D002244:Carbon; D006859:Hydrogen