Abstract
The mechanism of the NHC-catalyzed intermolecular Stetter reaction between benzaldehyde and cyclopropene has been investigated using the PCM-M062X/6-311++G(3df,2p)//M062X/6-31+G(d,p) level of DFT. Compared to the direct reaction, a substantial reduction in the activation free energy by 10.6-14.4 kcal/mol is observed when the reaction is performed in the presence of water, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), and 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU). The bases promote the proton transfer step of the reaction to yield the Breslow intermediate. An early concerted transition state has been located for the stereocontrolling C-C bond formation step (ΔG# = 26.6 kcal/mol) which is used to explain the diastereomeric ratio observed in the experiment.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 7144-7146 |
| Number of pages | 3 |
| Journal | Tetrahedron Letters |
| Volume | 54 |
| Issue number | 52 |
| DOIs | |
| State | Published - Dec 25 2013 |
Bibliographical note
Funding Information:We thank the support from the Council of Scientific and Industrial Research (CSIR), Government of India through the project CSC0129 . A.M.J. is thankful to UGC, Government of India for a fellowship.
Keywords
- Breslow intermediate
- Density functional theory
- N-Heterocyclic carbene
- Organocatalysis
- Stetter reaction
ASJC Scopus subject areas
- Biochemistry
- Drug Discovery
- Organic Chemistry