N‑Heterocyclic Carbene-Catalyzed 1,4-Alkylacylation of 1,3-Enynes

The radical relay coupling reaction recently emerged as a powerful synthetic strategy for producing tetrasubstituted allenes. However, bond-forming processes involving the allenyl radical intermediate are mostly limited to those promoted by transition metals. In this report, we describe that a ketyl...

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Veröffentlicht in:Organic letters 2021-12, Vol.23 (23), p.9251-9255
Hauptverfasser: Cai, Yuxing, Chen, Jiean, Huang, Yong
Format: Artikel
Sprache:eng
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Zusammenfassung:The radical relay coupling reaction recently emerged as a powerful synthetic strategy for producing tetrasubstituted allenes. However, bond-forming processes involving the allenyl radical intermediate are mostly limited to those promoted by transition metals. In this report, we describe that a ketyl radical generated from single-electron oxidation of the Breslow intermediate is an excellent coupling partner of allenyl radicals. An organocatalytic 1,4-alkylacylation of 1,3-enynes occurred smoothly in the presence of an aldehyde, a radical precursor, and an N-heterocyclic carbene catalyst. This transformation showed remarkable tolerance to both aromatic and aliphatic aldehydes, enyne substitution, and diversified radical precursors.
ISSN:1523-7060
1523-7052
DOI:10.1021/acs.orglett.1c03601