Synfacts 2013; 9(1): 0037
DOI: 10.1055/s-0032-1317881
Synthesis of Materials and Unnatural Products
© Georg Thieme Verlag Stuttgart · New York

Precisely Defined Electron-Rich Oligopyrroles

Contributor(s):
Timothy M. Swager
,
Jonathan G. Weis
Kaschel J, Schneider TF, Kratzert D, Stalke D, Werz DB * Georg-August-Universität Göttingen, Germany
Domino Reactions of Donor–Acceptor-Substituted Cyclopropanes for the Synthesis of 3,3′-Linked Oligopyrroles and Pyrrolo[3,2-e]indoles.

Angew. Chem. Int. Ed. 2012;
51: 11153-11156
Further Information

Publication History

Publication Date:
17 December 2012 (online)

 

Significance

The authors report the synthesis of 3,3′-linked oligopyrroles through the domino ring-enlargement of cyclopropanes. In one step, furan is converted into 2, which is subsequently transformed into diketone 3 via Weinreb-ketone synthesis. Refluxing with catalytic acid in benzene with an aniline, yielded the desired bispyrrole products 4. Unsurprisingly, the electron-rich anilines provided significantly higher yields than the electron-poor anilines.


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Comment

Extended oligoacetalic diketone 5 was synthesized and subsequently converted into quarter-pyrrole 6 in 25% yield. This is the first electron-rich, precisely defined oligopyrrole reported and it is noteworthy due the inherent instability of electron-rich oligopyrrolic systems.


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