Easy access to medium rings by entropy/strain reduction, Part 3. Competition between dihydroazepine and enamine formation in reaction of tetrahalosubstituted dibromides with primary amines

✍ Scribed by James G. Walsh; Declan G. Gilheany

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2002
• Tongue: English
• Weight: 48 KB
• Volume: 39
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570390624

✦ Synopsis

Abstract

The reaction of Z,Z‐2,3,4,5‐tetrahalo‐2,4‐dien‐1,6‐dibromides (3, R^1^ ‐ R^4^ = Cl, Br) with primary amines in the presence of potassium carbonate leads to both the dihydroazepines 4 and secondary enamines 5. The formation of enamine is suppressed with toluene sulfonamide as nitrogen source. (2Z,4Z)‐2,3,4,5‐Tetrabromo‐hexa‐2,4‐diene‐1,6‐diol (2, R^1^ ‐ R^4^ = Br) is atropisomeric in solution.