70158-21-3Relevant articles and documents
Photoredox Catalysis of Aromatic β-Ketoesters for in Situ Production of Transient and Persistent Radicals for Organic Transformation
Chen, Bin,Feng, Ke,Guo, Jia-Dong,Tung, Chen-Ho,Wu, Li-Zhu,Xiao, Hongyan,Yang, Xiu-Long
supporting information, p. 5365 - 5370 (2020/02/28)
Radical formation is the initial step for conventional radical chemistry. Reported herein is a unified strategy to generate radicals in situ from aromatic β-ketoesters by using a photocatalyst. Under visible-light irradiation, a small amount of photocatalyst fac-Ir(ppy)3 generates a transient α-carbonyl radical and persistent ketyl radical in situ. In contrast to the well-established approaches, neither stoichiometric external oxidant nor reductant is required for this reaction. The synthetic utility is demonstrated by pinacol coupling of ketyl radicals and benzannulation of α-carbonyl radicals with alkynes to give a series of highly substituted 1-naphthols in good to excellent yields. The readily available photocatalyst, mild reaction conditions, broad substrate scope, and high functional-group tolerance make this reaction a useful synthetic tool.
Addition of mixed (Alkenyl)dialkylzincates to vicinal diketo esters
Selter, Lars,Harms, Klaus,Koert, Ulrich
, p. 1215 - 1230 (2017/12/07)
Methods for the regioselective alkylation, arylation, and alkenylation of α,β-diketo esters using organozinc reagents are reported. Alkylation and arylation at the α-position is possi-ble using diorganozinc compounds. Alkenylation can be achieved using mixed (alkenyl)dineopentylzincates.
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
supporting information, p. 1548 - 1554 (2016/06/01)
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).
