Erratum: Indium-catalyzed cycloisomerizations of cyclopropene-3,3- dicarbonyl compounds: Efficient access to benzo-fused heteroaromatics and heterobiaryls (Angewandte Chemie - International Edition (2012) 51 (3198-3202) DOI: 10.1002/anie.201107717)

Full text of DOI:10.1002/anie.201301502

Angewandte
Chemie
.
Angewandte
Corrigendum
Upon further 2D NMR spectroscopic studies, the authors of this Communication
discovered that their initial assignment of several cyclopropenes was incorrect.
Compounds 3a, 3b, and 3d–3m 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 3a and 3n are formed in 56 and 52% yield,
respectively (see the updated Scheme 2).
Indium-Catalyzed Cycloisomerizations of
Cyclopropene-3,3-Dicarbonyl
Compounds: Efficient Access to Benzo-
Fused Heteroaromatics and
Heterobiaryls
L. H. Phun, J. Aponte-Guzman,
S. France*
3198–3202
When the cyclopropenations are performed with [Rh2(Oct)4] or [Rh2(S-PTAD)4] at
À458C, in each case the cyclopropenes were formed preferentially. However, cyclo-
propenes 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.
Angew. Chem. Int. Ed. 2012, 51
DOI: 10.1002/anie.201107717
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).
The authors apologize for this mistake.
Table 1: In(OTf)3-catalyzed cyclopropene cycloisomerizations.[a]
Entry
1
3
4
t [h] Yield [%]
12
8
15(86)[d]
63(86)[d]
86
2
3
12
[e]
4
5
–
–
24
24
–
[e]
–
Scheme 2. Rhodium(II)-catalyzed cyclopropenation.
6
7
7.5
7
29(68)[d]
25(83)[d]
[a] Reactions run with cyclopropene (1 equiv) and In(OTf)3 (5 mol%) in
CH2Cl2 at 258C. [b] Yields of product isolated after column chromato-
graphy. [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.
Angew. Chem. Int. Ed. 2013, 52, 5657 – 5669
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