title: Cobalt-Catalyzed sp(2) -C-H Activation: Intermolecular Heterocyclization with Allenes at Room Temperature.
abstract: The reactivity of allenes in transition-metal-catalyzed C-H activation chemistry is governed by the formation of either alkenyl-metal (M-alkenyl) or metal-π-allyl intermediates. Although either protonation or a β-hydride elimination is feasible with a M-alkenyl intermediate, cyclization has remained unexplored to date. Furthermore, due to the increased steric hindrance, the regioselectivity for the intramolecular cyclization of the metal-π-allyl intermediate was hampered towards the more substituted side. To address these issues, a unified approach to synthesize a diverse array of biologically and pharmaceutically relevant heterocyclic moieties by cobalt-catalyzed directed C-H functionalization was envisioned. Upon successful implementation, the present strategy led to the regioselective formation of dihydroisoquinolin-1(2H)-ones, isoquinolin-1(2H)-ones, dihydropyridones, and pyridones.
authors: Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India. uluiict@gmail.com.
authors: Neetipalli
authors: N
authors: Thrimurtulu
authors: Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
authors: Arnab
authors: A
authors: Dey
authors: Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India. dmaiti@chem.iitb.ac.in.
authors: Debabrata
authors: D
authors: Maiti
authors: Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India. chandra.volla@chem.iitb.ac.in.
authors: Chandra M R
authors: CM
authors: Volla
keywords: C−H activation; cobalt catalysts; heterocyclization; metal intermediates