70158-21-3Relevant academic research and scientific papers
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.
Mechanochemical electrophilic fluorination of liquid beta-ketoesters
Howard, Joseph L.,Sagatov, Yerbol,Browne, Duncan L.
, p. 3118 - 3123 (2017/12/26)
An improved substrate scope for the mechanochemical electrophilic fluorination of dicarbonyls is reported. The applicable substrates have now been broadened to include liquid β-ketoesters. Key to this capability is the inclusion of a grinding auxiliary (NaCl) to improve mass transfer and prevent pasting or gumming of the reaction mixture. Notably, the use of a small amount of acetonitrile is critical to increasing the rate of reaction, ensuring complete consumption of starting materials during the short reaction times as well as improving the selectivity for the monofluorinated product in the mill.
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.
Cooperative Indium(III)/Silver(I) System for Oxidative Coupling/Annulation of 1,3-Dicarbonyls and Styrenes: Construction of Five-Membered Heterocycles
Ko, Tae Yun,Youn, So Won
supporting information, p. 1934 - 1941 (2016/07/06)
A cooperative indium(III)/silver(I) system for the synthesis of various five-membered heterocycles, including dihydrofurans, pyrroles, spirolactones, and spiroiminolactones, through the sequential oxidative coupling/annulation reaction of 1,3-dicarbonyl compounds with styrenes has been developed. Four different heterocyclic systems were successfully synthesized depending on the substitution pattern of the substrates using readily available starting materials. This system has the advantages of a broad substrate scope, moderate to good chemical yields, an operationally easy and simple procedure, and short reaction times. (Figure presented.) .
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).
Straightforward enantioselective access to γ-butyrolactones bearing an all-carbon β-quaternary stereocenter
Meninno, Sara,Fuoco, Tiziana,Tedesco, Consiglia,Lattanzi, Alessandra
supporting information, p. 4746 - 4749 (2015/04/27)
An enantioselective one-pot aldol/lactonization sequence has been developed to access highly challenging γ-butyrolactones bearing an all-carbon quaternary stereocenter at the β-position by reacting acylated succinic esters with aqueous formaldehyde in the presence of 3 mol % loading of a cinchona alkaloid-derived squaramide providing direct access to paraconic acid derivatives in high yield and fairly good level of enantioselectivity (up to 88% ee).
