Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, 402 N Blackford St, Indianapolis, Indiana 46202, USA.
Chemistry Department, Western Kentucky University, Bowling Green, KY 42101, USA.
Chem Commun (Camb). 2021 May 27;57(43):5254-5257. doi: 10.1039/d1cc02016a.
The first photoinduced synthesis of polyfunctionalized 3-aza[n.1.0]bicycles from readily available ene-ynamides and 2,6-lutidine N-oxide using an organic acridinium photocatalyst is reported. Applying a photocatalytic strategy to the reactive distonic cation vinyl radical intermediate from ynamide, a series of bio-valuable 3-azabicycles, including diverse 3-azabicyclio[4.1.0]heptanes and 3-azabicyclo[5.1.0]octanes that are challenging to accomplish using traditional methods, have been successfully synthesized in good to high yields under mild and metal-free conditions. Mechanistic studies are consistent with the photocatalyzed single-electron oxidation of ene-ynamide and the intermediacy of a putative cationic vinyl radical in this transformation. Importantly, this strategy provides new access to the development of photocatalytic vinyl radical cascades for the synthesis of structurally sophisticated substrates.
本文报道了首例通过易得的烯基酰胺和 2,6- 二甲基吡啶 N- 氧化物，在有机吖啶光催化剂作用下，光诱导合成多官能化 3-氮杂[1.0]双环的反应。在吖啶鎓光催化反应中，通过将反应性离域正碳离子乙烯基自由基中间体应用于反应中，我们成功地在温和、无金属条件下，以良好到较高的产率，合成了一系列生物有价值的 3-氮杂双环[4.1.0]庚烷和 3-氮杂双环[5.1.0]辛烷等具有挑战性的化合物，这些化合物难以通过传统方法来合成。该反应的机理研究表明，烯基酰胺的光催化单电子氧化和假定的阳离子乙烯基自由基中间体在该转化中起重要作用。重要的是，该策略为合成结构复杂的底物的光催化乙烯基自由基级联反应提供了新的途径。
