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
Cerium photocatalyzed dehydrogenative lactonization of 2-arylbenzoic acids
作者:Ketan Wadekar、Suraj Aswale、Veera Reddy Yatham
DOI:10.1039/c9ob02676b
日期:——
The first cerium photocatalyzed dehydrogenative lactonization of 2-arylbenzoic acids has been developed. This operationally simple protocol allows rapid access to synthetically useful coumarins on gram scale by employing CeCl3 as a photocatalyst and O2 as a terminal oxidant. Overall, this delivers an economical and environmentally amiable entry to diversely substituted coumarins, important structural
<i>tert</i>-Butyl Nitrite-Mediated Synthesis of <i>N</i>-Nitrosoamides, Carboxylic Acids, Benzocoumarins, and Isocoumarins from Amides
作者:Subhash L. Yedage、Bhalchandra M. Bhanage
DOI:10.1021/acs.joc.7b00570
日期:2017.6.2
(TBN) as a multitask reagent for (1) the controlled synthesis of N-nitrosoamide from N-alkyl amides, (2) hydrolysis of N-methoxyamides to carboxylic acids, (3) metal- and oxidant-free benzocoumarin synthesisfrom ortho-aryl-N-methoxyamides via N–H, C–N, and C–H bond activation, and (4) isocoumarin synthesisusingRu(II)/PEG as a recyclable catalytic system via ortho-C–H activation and TBN as an oxygen source
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。
Microwave-Assisted Cyclization under Mildly Basic Conditions: Synthesis of 6<i>H</i>-Benzo[<i>c</i>]chromen-6-ones and Their 7,8,9,10-Tetrahydro Analogues
作者:Pham Duy Quang Dao、Son Long Ho、Ho-Jin Lim、Chan Sik Cho
DOI:10.1021/acs.joc.8b00048
日期:2018.4.6
give the corresponding 6H-benzo[c]chromen-6-ones and their 7,8,9,10-tetrahydro analogues, respectively, in 50–72% yields. Aryl 3-bromoacrylates are also converted into 2H-chromen-2-ones under the employed conditions.
在K 2 CO 3的存在下,在二甲基甲酰胺中通过微波辐照,将2-溴苯甲酸芳酯和2-溴环己-1-芳烷基芳酯环化,得到相应的6 H-苯并[ c ] chromen-6-one及其7,8, 9,10-四氢类似物,产率分别为50-72%。在所采用的条件下,将3-溴丙烯酸芳基酯也转化为2 H-铬-2-基。