Base-promoted cascade β-F-elimination/electrocyclization/Diels–Alder/retro-Diels–Alder reaction: efficient access to δ-carboline derivatives

• Published in: Chemical science (Cambridge) Vol. 13; no. 35; pp. 10448 - 10454
• Main Authors: Sun, Xi-Shang, Diao, Xin-Yu, Dong, Xiu-Qin, Wang, Chun-Jiang
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 15.08.2022; The Royal Society of Chemistry
• Subjects: Alkynes; Chemistry; Diels-Alder reactions; Esters; Ferric ions; Reaction intermediates; Substrates
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/d2sc03166c

A serendipitous and highly efficient approach for the construction of a variety of δ-carboline derivatives was developed through base-promoted cascade β-F-elimination/electrocyclization/Diels–Alder/retro-Diels–Alder reaction of N -2,2,2-trifluoroethylisatin ketoimine esters with alkynes in good to high yields with excellent regio-/chemoselectivity control. Moreover, a reasonable reaction pathway was proposed, which was in accordance with the prepared reaction intermediate and control experiment results. The δ-carboline product could be easily converted into a new chiral Py-box-type ligand through simple synthetic transformations. This salient strategy featured the advantages of metal-free conditions, excellent regio-/chemoselectivity, good to high yields, and outstanding substrate tolerance. Importantly, the potential application of these fascinating δ-carboline derivative products is well demonstrated in the recognition of ferric ions.