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Synfacts 2011(11): 1185-1185  
DOI: 10.1055/s-0031-1289239
Synthesis of Materials and Unnatural Products
© Georg Thieme Verlag Stuttgart ˙ New York

Expanded Cyclo[8]pyrroles Made Easy

Contributor(s): Timothy M. Swager, Sébastien Rochat
T. Okujima*, G. Jin, N. Matsumoto, J. Mack, S. Mori, K. Ohara, D. Kuzuhara, C. Ando, N. Ono, H. Yamada, H. Uno, N. Kobayashi*
Ehime University, Matsuyama and Tohoku University, Sendai, Japan
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Publication History

Publication Date:
19 October 2011 (online)

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Significance

Cyclo[8]isoindole 3 is prepared by retro-Diels-Alder reaction of 2 under thermal conditions. The optimized synthesis of compound 2 is based on oxidative homocoupling of 1 in the presence of Ce(IV) as oxidant and SO4 ²- as template. Optical properties of compound 2 and 3 are explored and rationalized based on magnetic circular dichroism spectroscopy and DFT calculations. X-ray crystallography revealed that cyclo[8]pyrrole 2 possesses a near-planar geometry, whereas compound 3 is strongly distorted owing to steric hindrance between the neighboring benzene rings.