Concise Synthesis of Thiazolo[4,5-b]indoles via Ring Switch/Cyclization Sequences

The unexpected reactions of indoline hemiaminals affords 2,5-diaryl-4-hydroxythiazolines through a thioamidation/ring switch sequence. The key to success of this transformation is to use a thioamide as a thiazoline precursor under transient tautomeric control. This transformation features mild reaction conditions and good yields with broad functional group tolerance (17 examples, up to 99 % yield). Further transformations of the thiazolines provide a direct entry to dihydrothiazolo[4,5-b]indoles and thiazolo[4,5-b]indoles.

This is the peer reviewed version of the following article: [K. Yamada, T. Tsubogo, H. Kanazawa, S. Ishizuka, K. Ohyama, M. Kaida, T. Abe, Eur. J. Org. Chem. 2024, 27, e202301130. https://doi.org/10.1002/ejoc.202301130], which has been published in final form at [https://doi.org/10.1002/ejoc.202301130]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.

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