56015-90-8Relevant articles and documents
Highly effective C-C bond cleavage of lignin model compounds
Wang, Yinling,Wang, Qianyi,He, Jianghua,Zhang, Yuetao
supporting information, p. 3135 - 3141 (2017/07/24)
A highly effective method is developed for the C-C bond cleavage of lignin model compounds. The inert Cα-Cβ or Cα-Cphenyl bond of oxidized lignin model compounds was successfully converted to an active ester bond through the classic organic name reaction, Baeyer-Villiger (BV) oxidation, and thus acetal esters and aryl esters were produced in high yields (up to 99%) at room temperature. Next, K2CO3 catalyzed the alcoholysis of the resulting ester products at 45 °C, affording various useful chemical platforms in excellent yields (up to 99%), such as phenols and multifunctional esters. This method uses commercially available reagents, is transition-metal free and simple, but highly effective, and involves mild reaction conditions.
Efficient transesterification/acylation reactions mediated by N-heterocyclic carbene catalysts
Grasa, Gabriela A.,Gueveli, Tatyana,Singh, Rohit,Nolan, Steven P.
, p. 2812 - 2819 (2007/10/03)
Imidazol-2-ylidenes, a family of N-heterocyclic carbenes (NHC), are efficient catalysts in the transesterification involving numerous esters and alcohols. Low catalyst loadings of aryl- or alkyl-substituted NHC catalysts mediate the acylation of alcohols with enol acetates in short reaction times at room temperature. Commercially available and more difficult to cleave methyl esters react with primary alcohols in the presence of alkyl-substituted NHC to efficiently form the corresponding esters. While primary alcohols are selectively acylated over secondary alcohols with use of enol esters as acylating agents, methyl and ethyl esters can be employed as protective agents for secondary alcohols in the presence of the more active alkyl-substituted NHC catalysts. The NHC-catalyzed transesterification protocol was simplified by generating the imidazol-2-ylidene catalysts in situ.
Improved ester interchange catalysts
Kissling, Rebecca M.,Gagne, Michel R.
, p. 4209 - 4212 (2007/10/03)
(equation presented) Mixed alkoxide/aryloxide clusters are long-lived and milder than previously reported ester interchange catalysts. They completely transform difficult substrates in a single synthetic operation with lower catalyst and reagent ester loadings. In addition to superior activities, these mixed clusters are kinetically less basic toward enolizable esters.
