Acid catalyzed coupling of aromatic aldehydes and methyldiazoacetate-a theoretical mechanistic study

作者：Dazinger Georg; Kirchner Karl A^*

来源：New Journal of Chemistry, 2012, 36(3): 781-788.

DOI：10.1039/c2nj20824e

The proton catalyzed reaction of methyldiazoacetate and benzaldehyde resulting in the formation of beta-ketoesters and 3-hydroxyacrylates has been investigated by means of DFT/B3LYP calculations. Experimentally this reaction is performed using HBF4 center dot Et2O as the catalyst and CH2Cl2 as the solvent. Several mechanistic pathways involving 1,2-migration of phenyl-, H-, and OH-substituents have been considered. In agreement with the experiment, phenyl migration is slightly favored over H-and OH-migrations and thus the formation of 3-hydroxyacrylates over beta-ketoesters takes place. Epoxide formation is not feasible in the presence of acid with non-nucleophilic counterions. Moreover, a counterion-assisted pathway has been also taken into account. The overall reaction is similar and competitive to the %26quot;BF4--free%26quot; pathway.

• 出版日期2012