A Palladium-Catalyzed Ullmann Cross-Coupling/Reductive Cyclization Route to the Carbazole Natural Products 3‑Methyl‑9H‑carbazole, Glycoborine, Glycozoline, Clauszoline K, Mukonine, and Karapinchamine A

The title natural products 2–7 have been prepared by reductive cyclization
of the relevant 2-arylcyclohex-2-en-1-one
(e.g. 20) to the corresponding tetrahydrocarbazole and
dehydrogenation (aromatization) of this to give the target carbazole
(e.g. 4). Compounds such as 20 were prepared
using a palladium-catalyzed Ullmann cross-coupling reaction between
the appropriate 2-iodocyclohex-2-en-1-one and o-halonitrobenzene.

标题为自然产物2-7的数据集，是通过相关2-取代环己-2-烯-1-酮（例如20）的还原环化反应制备相应的四氢咔唑，随后对其进行脱氢（芳构化）反应，以获得目标咔唑（例如4）。如20等化合物，是通过在适当的2-碘代环己-2-烯-1-酮与对-卤硝基苯之间进行钯催化Ullmann交叉偶联反应制备的。