Abstract
An efficient organocatalytic reaction using 1,3-nitro enynes with 4-hydroxycoumarin and 4-hydroxy-6-methyl-2-pyrone to afford pyrano-annulated scaffolds in high yield (up to 88% yield) and excellent stereoselectivities (up to >20:1 dr and >99% ee) is described. The reaction proceeded through sequential conjugate addition, allene formation, intramolecular oxa-Michael 6-endo-dig cyclization and DABCO-catalyzed olefin isomerization. A kinetic profile for isomerization was established. The mechanism for the organocascade reaction was proposed according to requisite computational and mechanistic experimental studies.
| Original language | English |
|---|---|
| Pages (from-to) | 3098-3101 |
| Number of pages | 4 |
| Journal | Organic Letters |
| Volume | 18 |
| Issue number | 13 |
| DOIs | |
| Publication status | Published - 2016 Jul 1 |
ASJC Scopus subject areas
- Biochemistry
- Physical and Theoretical Chemistry
- Organic Chemistry
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Cite this
Gurubrahamam, R., Gao, B. F., Chen, Y. M., Chan, Y. T., Tsai, M-K., & Chen, K. (2016). Organocascade Synthesis of Annulated (Z)-2-Methylenepyrans: Nucleophilic Conjugate Addition of Hydroxycoumarins and Pyranone to Branched Nitro Enynes via Allene Formation/Oxa-Michael Cyclization/Alkene Isomerization Sequence. Organic Letters, 18(13), 3098-3101. https://doi.org/10.1021/acs.orglett.6b01265