photocatalytic aerobicoxidative lactonization of arene C(sp2)–H bonds proceeds in the presence of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and tert-butyl nitrite (TBN). Under the optimized conditions, a range of 2-arylbenzoic acids is converted into the corresponding benzocoumarin derivatives in moderate to excellent yields. This method is characterized by its atom economy, mild reaction conditions, the
An efficient and robust methodology based on electrochemical techniques for the direct synthesis of aromatic lactones through dehydrogenative C−O cyclization is described. This new and useful electrochemical reaction can tolerate a variety of functional groups, and is scalable to 100 g under mild conditions. Remarkably, heterocycle‐containing substrates can be employed, thus expanding the scope of
Electrophilicity and nucleophilicity of commonly used aldehydes
作者:Sanjay Pratihar
DOI:10.1039/c4ob00555d
日期:——
The present approach for determining the electrophilicity (E) and nucleophilicity (N) of aldehydes includes a kinetic study of KMNO4 oxidation and NaBH4 reduction of aldehydes. A transition state analysis of the KMNO4 promoted aldehyde oxidation reaction has been performed, which shows a very good correlation with experimental results. The validity of the experimental method has been tested using the experimental activation parameters of the two reactions. The utility of the present approach is further demonstrated by the theoretical versus experimental relationship, which provides easy access to E and N values for various aldehydes and offers an at-a-glance assessment of the chemical reactivity of aldehydes in various reactions.
Electrochemical Intramolecular C-H/O-H Cross-Coupling of 2-Arylbenzoic Acids
作者:Ailong Shao、Na Li、Yong Gao、Jirui Zhan、Chien-Wei Chiang、Aiwen Lei
DOI:10.1002/cjoc.201800031
日期:2018.7
electro‐oxidative induced C—H activation of 2‐arylbenzoic acids has been developed. By using Na2SO4 aqueous solution as a cheap and green supporting electrolyte, different 2‐arylbenzoic acids could provide the corresponding lactones in 30%—90% yields. This reaction could be conducted on a gram scale with a good efficiency as well as a high utility for natural product synthesis.
已经开发了通过电氧化诱导的2-芳基苯甲酸的CH活化来合成内酯的方法。通过使用Na 2 SO 4水溶液作为廉价的绿色支持电解质,不同的2-芳基苯甲酸可以30%-90%的产率提供相应的内酯。该反应可以在克规模上高效地进行,并且对于天然产物的合成具有很高的实用性。