title: Ruthenium(II)-Catalyzed Regioselective Ortho Amidation of Imidazo Heterocycles with Isocyanates.
abstract: Direct ortho amidation at the phenyl ring of 2-phenylimidazo heterocycles with aryl isocyanates has been achieved via a chelation-assisted cationic ruthenium(II) complex catalyzed mechanism. The methodology provides a straightforward, high-yielding regioselective approach toward the synthesis of an array of ortho-amidated phenylimidazo heterocycles without prior activation of C(sp2)-H. This also reports the first method for coupling of aryl isocyanates with the imidazo[1,2-a]pyridine system via a pentacyclometalated intermediate. The methodology is found to be easily scalable and could be applied toward the selective ortho amidation of 2-heteroarylimidazo[1,2-a]pyridine frameworks.
authors.affiliation: Department of Chemistry, Birla Institute of Technology & Science , Pilani, Rajasthan 333031, India.
authors.forename: S M Abdul
authors.initials: SM
authors.lastname: Shakoor
authors.affiliation: Department of Chemistry, Birla Institute of Technology & Science , Pilani, Rajasthan 333031, India.
authors.forename: Santosh
authors.initials: S
authors.lastname: Kumari
authors.affiliation: Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali , Sector 81, S.A.S. Nagar, Manuali P.O., Punjab 140306, India.
authors.forename: Sadhika
authors.initials: S
authors.lastname: Khullar
authors.affiliation: Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali , Sector 81, S.A.S. Nagar, Manuali P.O., Punjab 140306, India.
authors.forename: Sanjay K
authors.initials: SK
authors.lastname: Mandal
authors.affiliation: Department of Chemistry, Birla Institute of Technology & Science , Pilani, Rajasthan 333031, India.
authors.forename: Anil
authors.identifier: 0000-0003-4699-3178
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Department of Chemistry, Birla Institute of Technology & Science , Pilani, Rajasthan 333031, India.
authors.forename: Rajeev
authors.identifier: 0000-0002-9284-9137
authors.initials: R
authors.lastname: Sakhuja