1261665-95-5Relevant articles and documents
Studies of the Electronic Effects of Zinc Cluster Catalysts and Their Application to the Transesterification of β-Keto Esters
Agura, Kazushi,Hayashi, Yukiko,Wada, Mari,Nakatake, Daiki,Mashima, Kazushi,Ohshima, Takashi
, p. 1548 - 1554 (2016)
The electronic effects of tetranuclear zinc cluster catalysts on transesterification were investigated by changing the carboxylate ligands in the clusters. High catalyst activity crucially depended on the balance between Lewis acidity and Br?nsted basicity of the catalyst; this was consistent with the dual activation of both the electrophile and nucleophile by the cooperative zinc centers. In addition, tetranuclear zinc cluster catalysts achieved the transesterification of β-keto esters with unprecedented levels of broad substrate generality, in which a newly developed pentafluoropropionate-bridged zinc cluster and 4-dimethylaminopyridine additive greatly improved the reactivity of sterically congested α- and α,α-disubstituted β-keto esters. Lewis versus Br?nsted: High catalyst activity of zinc clusters on transesterification crucially depend on a balance between Lewis acidity and Br?nsted basicity of the catalyst. Zinc clusters, including a newly developed pentafluoropropionate-bridged zinc cluster, achieved the transesterification of β-keto esters with unprecedented levels of broad substrate generality (see figure).
