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Use of Molecular Oxygen as a Reoxidant in the Synthesis of 2-Substituted Benzothiazoles via Palladium-Catalyzed C![[BOND]](http://onlinelibrarystatic.wiley.com/undisplayable_characters/00f8ff.gif)
H Functionalization/Intramolecular CS Bond Formation
Article first published online: 12 OCT 2010
DOI: 10.1002/adsc.201000604
Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Additional Information
How to Cite
Inamoto, K., Hasegawa, C., Kawasaki, J., Hiroya, K. and Doi, T. (2010), Use of Molecular Oxygen as a Reoxidant in the Synthesis of 2-Substituted Benzothiazoles via Palladium-Catalyzed CH Functionalization/Intramolecular CS Bond Formation. Adv. Synth. Catal., 352: 2643–2655. doi: 10.1002/adsc.201000604
Publication History
- Issue published online: 20 OCT 2010
- Article first published online: 12 OCT 2010
- Manuscript Received: 29 JUL 2010
Funded by
- Grant-in-Aid forYoung Scientists (B)
- Japan Society for the Promotion of Science (JSPS)
Keywords:
- benzothiazoles;
- CH functionalization;
- CS bond formation;
- cyclization;
- molecular oxygen;
- palladium
Abstract
Molecular oxygen (O2) was successfully employed as a reoxidant in cyclizations of thiobenzanilides 1a–s through a palladium-catalyzed CH functionalization/intramolecular CS bond formation process, leading to an efficient, green method for the synthesis of 2-arylbenzothiazoles 2a–s. Addition of cesium fluoride (CsF) greatly enhanced the reactions, which produced variously substituted 2-arylbenzothiazoles with good functional group tolerance. Thioureas 4a–j were also found to be suitable substrates for the cyclization process using a palladium/O2 catalyst system, thus generating 2-aminobenzothiazoles 5a–j. One-pot syntheses of 2-aminobenzothiazoles 5a–j from aryl isothiocyanates 6 and amines 7 were also successful.