title: Intramolecular Dehydrogenative Coupling of 2,3-Diaryl Acrylic Compounds: Access to Substituted Phenanthrenes.
abstract: A simple, facile, and environmentally benign intramolecular dehydrogenative coupling of various 1,2-diarylethylenes for the synthesis of phenanthrenes in excellent yield has been described. This new methodology uses ceric ammonium nitrate (CAN) as a promoter at room temperature and has been extended to intermolecular synthesis of biaryl compounds. The electron transfer from methoxyarene to cerium leads to cationic radical formation, which further proceeds to intramolecular coupling. Preliminary mechanistic investigation by EPR spectroscopy and density functional theory calculation suggested a similar view.
authors.affiliation: Department of Chemistry, Indian Institute of Technology , Delhi, Hauz Khas, New Delhi, 110016, India.
authors.forename: Vijay
authors.initials: V
authors.lastname: Gupta
authors.affiliation: Department of Chemistry, Indian Institute of Technology , Delhi, Hauz Khas, New Delhi, 110016, India.
authors.forename: V U Bhaskara
authors.initials: VU
authors.lastname: Rao
authors.affiliation: Physical and Materials Chemistry Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411008, India.
authors.forename: Tamal
authors.initials: T
authors.lastname: Das
authors.affiliation: Physical and Materials Chemistry Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411008, India.
authors.forename: Kumar
authors.initials: K
authors.lastname: Vanka
authors.affiliation: Department of Chemistry, Indian Institute of Technology , Delhi, Hauz Khas, New Delhi, 110016, India.
authors.forename: Ravi P
authors.initials: RP
authors.lastname: Singh