C-H Bond activation of 2-isobutylthiazole at C5 position catalysed by Pd-N-heterocyclic carbene complexes

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Bugday N., Khan S., YAŞAR S., ÖZDEMİR İ.

JOURNAL OF ORGANOMETALLIC CHEMISTRY, vol.937, 2021 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 937
  • Publication Date: 2021
  • Doi Number: 10.1016/j.jorganchem.2021.121730
  • Journal Name: JOURNAL OF ORGANOMETALLIC CHEMISTRY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Chemical Abstracts Core, Chimica, Compendex
  • Keywords: Palladium, C-H activation, direct arylation, Thiazole, N-heterocyclic carbene
  • Open Archive Collection: AVESIS Open Access Collection
  • Inonu University Affiliated: Yes

Abstract

A highly efficient and effective protocol has been developed for the synthesis of C5-(hetero)arylated 2-isobutylthiazole derivatives. Four different palladium N-heterocyclic carbene (Pd-NHCs) complexes [Pd(mu-Cl)Cl(SIMes)](2) (2), (LCl2 Pd-SIMes) (3: L = PPh3; 4: L = Py; 5: L = 3-CHO-Py) were synthesized and used for the first time as a catalysts in direct C-H arylation reaction of 2-isobutylthiazole at C5 position. Utilizations of these catalytic systems, the arylation of 2-isobutylthiazole with substituted (hetero)aryl bromides efficiently proceeded at low catalyst loading (1 mol%) and without any additives such as PivOH under argon or aerobic conditions at 120 degrees C in a short time. Different substituted (hetero)aryl bromides, even some deactivated or highly sterically hindered (hetero)arylbromides, with a wide range of functional groups were successfully utilized under the optimum reaction conditions. In all cases, the C5 arylated 2-isobutylthiazoles were obtained in moderate to excellent yields. (C) 2021 Elsevier B.V. All rights reserved.