Pendant Alkoxy Groups on N-Aryl Substitutions Drive the Efficiency of Imidazolylidene Catalysts for Homoenolate Annulation from Enal and Aldehyde was written by Kyan, Ryuji;Sato, Kohei;Mase, Nobuyuki;Narumi, Tetsuo. And the article was included in Angewandte Chemie, International Edition in 2020.Reference of 80866-76-8 This article mentions the following:
Hydrogen-transfer in the tetrahedral intermediate generated from an imidazolylidene catalyst and α,β-unsaturated aldehyde forms a conjugated Breslow intermediate. This is a critical step affecting the efficiency of the NHC-catalyzed γ-butyrolactone formation via homoenolate addition to aryl aldehydes. A novel type of imidazolylidene catalyst with pendant alkoxy groups on the ortho-N-aryl groups is described. Catalyst of this sort facilitates the formation of the conjugated Breslow intermediate. Studies of the rate constants for homoenolate annulation affording γ-butyrolactones, reveal that introduction of the oxygen atoms in the appropriate position of the N-aryl substituents can increase the efficiency of imidazolylidene catalysts. Structural and mechanistic studies revealed that pendant alkoxy groups can be located close to the proton of the tetrahedral intermediate, thereby facilitating the proton transfer. In the experiment, the researchers used many compounds, for example, (3-Methyl-2-nitrophenyl)methanol (cas: 80866-76-8Reference of 80866-76-8).
(3-Methyl-2-nitrophenyl)methanol (cas: 80866-76-8) belongs to alcohols. Alkyl halides are often synthesized from alcohols, in effect substituting a halogen atom for the hydroxyl group. Converting an alcohol to an alkene requires removal of the hydroxyl group and a hydrogen atom on the neighbouring carbon atom. Dehydrations are most commonly carried out by warming the alcohol in the presence of a strong dehydrating acid, such as concentrated sulfuric acid.Reference of 80866-76-8
Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts