Brønsted Acid‐Mediated Annulation of α‐Oxo Ketene Dithioacetals with Pyrroles: Efficient Synthesis of Structurally Diverse Cyclopenta[b]pyrroles. Issue 26 (25th May 2015)

• Record Type: Journal Article
• Authors: Yang, Xiaoge; Wu, Kaikai; Wu, Ping; Chen, Jiping; Sun, Chenglin; Yu, Zhengkun
• Is Part Of: Chemistry. Volume 21:Issue 26(2015)
• Page Start: 9323
• Page End: 9327
• Publication Date: 2015-05-25
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201501022
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Brønsted acid‐mediated annulation of internal olefins α‐oxo ketene dithioacetals to pyrroles was efficiently achieved to afford cyclopenta[<italic>b</italic>]pyrroles. A pair of Brønsted acids with acid strengths, that is, trifluoroacetic acid, and <italic>para</italic>‐toluenesulfonic acid hydrate, were applied to promote the annulation reactions. The resultant products were readily oxidized to sulfones by <italic>meta</italic>‐chloroperoxybenzoic acid. Subsequent treatment with 1, 8‐diazabicyclo[5.4.0]undec‐7‐ene gave desulfurized terminal olefins or [2+2] cycloaddition products from the desulfurized olefin intermediates. The present protocol provides facile access to structurally diverse cyclopenta[<italic>b</italic>]pyrrole derivatives under mild conditions.</p> </abstract>