Ajitha, Manjaly J. ; Suresh, Cherumuttathu H. (2013) Role of base assisted proton transfer in N-heterocyclic carbene-catalyzed intermolecular Stetter reaction Tetrahedron Letters, 54 (52). pp. 7144-7146. ISSN 00404039
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Official URL: http://doi.org/10.1016/j.tetlet.2013.10.116
Related URL: http://dx.doi.org/10.1016/j.tetlet.2013.10.116
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.
| Item Type: | Article |
|---|---|
| Source: | Copyright of this article belongs to Elsevier Ltd. |
| Keywords: | Organocatalysis, N-Heterocyclic carbene, Stetter reaction, Breslow intermediate, Density functional theory |
| ID Code: | 127392 |
| Deposited On: | 13 Oct 2022 09:39 |
| Last Modified: | 13 Oct 2022 09:39 |
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