We thank Prof. Shuhei Fujinami (Kanazawa University) for X-ray crystallographic analysis and Mio Hashizume for technical assistance. This study was partially supported by the Kurata Memorial Hitachi Science and Technology Foundation and JSPS KAKENHI Grant Number 24590007.
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Communication
Regioselective Inter- and Intramolecular Formal [4+2] Cycloaddition of Cyclobutanones with Indoles and Total Synthesis of (±)-Aspidospermidine†
Article first published online: 26 NOV 2012
DOI: 10.1002/anie.201206734
Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Additional Information
How to Cite
Kawano, M., Kiuchi, T., Negishi, S., Tanaka, H., Hoshikawa, T., Matsuo, J.-i. and Ishibashi, H. (2013), Regioselective Inter- and Intramolecular Formal [4+2] Cycloaddition of Cyclobutanones with Indoles and Total Synthesis of (±)-Aspidospermidine . Angew. Chem. Int. Ed., 52: 906–910. doi: 10.1002/anie.201206734
- †
Publication History
- Issue published online: 11 JAN 2013
- Article first published online: 26 NOV 2012
- Manuscript Revised: 30 OCT 2012
- Manuscript Received: 20 AUG 2012
Funded by
- Kurata Memorial Hitachi Science and Technology Foundation
- JSPS. Grant Number: 24590007
Keywords:
- alkaloids;
- cycloaddition;
- Lewis acids;
- regioselectivity;
- total synthesis
This way and that way: A formal [4+2] cycloaddition between various cyclobutanones and indoles proceeded efficiently under Lewis acid catalysis (see scheme; PG = protecting group). The regioselectivity of the reaction could be controlled in such a way that each of the two possible regioisomers of a cycloaddition product could be synthesized selectively. The usefulness of this reaction for the total synthesis of hydrocarbazole natural products was demonstrated.