(4+3) Cycloaddition Reactions of N‐Alkyl Oxidopyridinium Ions. (16th October 2017)

• Record Type: Journal Article
• Authors: Fu, Chencheng; Lora, Nestor; Kirchhoefer, Patrick L.; Lee, Dong Reyoul; Altenhofer, Erich; Barnes, Charles L.; Hungerford, Natasha L.; Krenske, Elizabeth H.; Harmata, Michael
• Is Part Of: Angewandte Chemie. Volume 129:Number 46(2017)
• Page Start: 14874
• Page End: 14879
• Publication Date: 2017-10-16
• Subjects: Alkaloide -- (4+3)-Cycloaddition -- Diene -- Pyridinium-Ionen; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201708320
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: N ‐Methylation of methyl 5‐hydroxynicotinate followed by reaction with a diene in the presence of triethylamine afforded (4+3) cycloadducts in good to excellent yields. High regioselectivity was observed with 1‐substituted and 1, 2‐disubstituted butadienes. Density functional theory calculations indicate that the cycloaddition involves concerted addition of the diene onto the oxidopyridinium ion. The process provides rapid access to bicyclic nitrogenous structures resembling natural alkaloids.