[a] Reactions run with cyclopropene (1 equiv) and In(OTf)3 (5 mol %) in CH2Cl2 at 25 °C. [b] Yields of product isolated after column chromatography. [c] Not isolated and used crude due to instability. [d] Values in parentheses represent the yields obtained when the furan 3′ was employed under the reaction conditions. [e] No reaction after 24 h.
Corrigendum: Indium-Catalyzed Cycloisomerizations of Cyclopropene-3,3-Dicarbonyl Compounds: Efficient Access to Benzo-Fused Heteroaromatics and Heterobiaryls
Article first published online: 17 MAY 2013
Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Angewandte Chemie International Edition
Volume 52, Issue 22, page 5669, May 27, 2013
How to Cite
- Issue published online: 17 MAY 2013
- Article first published online: 17 MAY 2013
Vol. 51, Issue 13, 3198–3202, Article first published online: 16 FEB 2012
- diazo compounds;
- small ring systems;
- strained molecules
Upon further 2D NMR spectroscopic studies, the authors of this Communication discovered that their initial assignment of several cyclopropenes was incorrect. Compounds 3 a, 3 b, and 3 d–3 m are actually furan derivatives. Under the reported cyclopropenation conditions (with [Rh2esp2]), the product is either the furan or the cyclopropene, depending on the nature of the alkyne substituent: with R = 4-MeOC6H4, Ph, 4-CF3C6H4, nBu, and 2-thienyl, the furan 3′ is formed in 32–87% yield, while with R = 4-BrC6H4 and TMS, cyclopropenes 3 a and 3 n are formed in 56 and 52% yield, respectively (see the updated Scheme 2).
When the cyclopropenations are performed with [Rh2(Oct)4] or [Rh2(S-PTAD)4] at −45 °C, in each case the cyclopropenes were formed preferentially. However, cyclopropenes bearing electron-donating groups (4-MeOC6H4, nBu, CH2TMS, and 2-thienyl) could not be isolated by flash chromatography. These cyclopropenes can be generated in situ and reacted further.
The furan derivatives undergo In(OTf)3-catalyzed ring-opening and reorganization through zwitterionic intermediates to give the observed benzo-fused products. In relation to the hypothesis in the manuscript, the cyclopropene substrates do proceed to the benzo-fused products as reported in the manuscript (see updated Table 1).
|Entry||3||4||t [h]||Yield [%]|
The authors apologize for this mistake.