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Synfacts 2007(11): 1137-1137  
DOI: 10.1055/s-2007-991299
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York

Synthesis of 2,3-Fused Indoles

Contributor(s): Victor Snieckus, Wei Gan
B. Bajtos, M. Yu, H. Zhao, B. L. Pagenkopf*
The University of Western Ontario, London, Canada and the University of Texas at Austin, USA
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Publication History

Publication Date:
23 October 2007 (online)

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Significance

Lewis acid initiated indole C-2/C-3 annulation and C-2 alkylation with alkoxylcyclopropanoate esters are reported. The stereochemistry of the product originates from the Re- and Si-face attack of the indole to the electrophile C which resulted from cyclopropane ring cleavage under Lewis acid mediated conditions (route A). When ­3-substitued indoles are involved, indole 2-alkylation occurs through route B via C-3 to C-2 migration. The cyclopropanes are easily prepared from reactions of enol ethers with ethyl diazoacetates.