title: Iodine mediated intramolecular C2-amidative cyclization of indoles: a facile access to indole fused tetracycles.
abstract: A novel and metal-free I2-mediated intramolecular C2 amidation of indoles under mild reaction conditions is developed. This methodology affords various indole fused tetracyclic compounds, such as benzo[4,5]imidazo[1,2-a]indoles by intramolecular C2 amidation of N-aryl substituted indoles. This C2 sulfonamidative cyclization also offers convenient access to indolo[2,3-b]indoles and dihydroindolo[2,3-b]quinoline from C3 aryl substituted indoles in good to excellent yields. Indolo[2,3-b]quinolines are also synthesized by the domino cyclization-detosylation-aromatization reaction sequence.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Madras, Chennai 600 036, Tamil Nadu, India. gsekar@iitm.ac.in.
authors.forename: Sindhura
authors.initials: S
authors.lastname: Badigenchala
authors.forename: Venkatachalam
authors.initials: V
authors.lastname: Rajeshkumar
authors.forename: Govindasamy
authors.initials: G
authors.lastname: Sekar