A bromide salt mediated neighboring ester-participated bromocyclization of o-alkynylbenzoates is described here for synthesis of benzil-o-carboxylate. 4-bromoisocoumarins are also reached when phenyl o-alkynylbenzoate is used as the substrate. Mechanism studies suggest that the whole process is comprised by electrophilic bromocyclization and dibromohydration-based ring-opening, and the neighboring
Trifluoromethylthiolation/Selenolation and Lactonization of 2-Alkynylbenzoate: The Application of Benzyl Trifluoromethyl Sulfoxide/Selenium Sulfoxides as SCF<sub>3</sub>/SeCF<sub>3</sub> Reagents
作者:Haofeng Shi、Xingzong Wang、Xiaoxian Li、Beibei Zhang、Xuemin Li、Jingran Zhang、Jingyue Yang、Yunfei Du
DOI:10.1021/acs.orglett.2c00563
日期:2022.3.25
The combined use of BnS(O)CF3/BnSe(O)CF3 with Tf2O as SCF3/SeCF3 reagents was implemented to realize an efficient synthesis of biologically interesting 4-(trifluoromethylthio/trifluoromethylseleno)isocoumarins from 2-alkynylbenzoates. The mechanistic pathway was postulated to involve formation of the electrophilic SCF3/SeCF3 species via interrupted Pummerer reactions followed by a concerted triflu
NBS-Mediated Oxygen Transfer Reaction of Carbonyl in Ester: Efficient Synthesis of Benzil-<i>o</i>
-carboxylate Derivative From <i>o</i>
-Alkynylbenzoate
diketonization. A plausible mechanism suggests that a bromo‐incoporated isocoumarin cation is described as an intermediate, and the whole process is constituted by NBS‐mediated electrophilic 6‐endo annulation and oxygen transferreaction through NBS‐mediated oxidative ring‐opening. Water serves as a nucleophile of ring‐opening.
Synthesis of Indeno[1,2-<i>c</i>]furans via Cobalt-Catalyzed Radical–Polar Crossover [3 + 2] Cycloaddition of <i>o</i>-Alkynylaryl β-Dicarbonyls
作者:Guo-Cai Yuan、Peng Guo、Zhi-Hua Wang、Lingyun Zhu、Xinglei He、Yuanming Li、Ke-Yin Ye
DOI:10.1021/acs.orglett.2c03297
日期:2022.11.11
Fused polycyclic furans are privileged structural scaffolds in materials chemistry, including organic semiconductors. Specifically, indeno[1,2-c]furans are an interesting type of polycyclic furans featuring a fused furan and indenone framework. Unfortunately, limited studies on their photophysical properties have been performed, probably owing to the lack of efficient and straightforward approaches
稠合多环呋喃是材料化学(包括有机半导体)中的特殊结构支架。具体来说,茚并[1,2- c ]呋喃是一种有趣的多环呋喃,具有稠合呋喃和茚酮骨架。不幸的是,对其光物理性质的研究有限,这可能是由于缺乏对这些化合物的有效和直接的方法。在此,我们开发了一种钴催化的自由基-极性交叉环化反应,使现成的o-炔基芳基 β-羰基化合物能够提供多种茚并 [1,2- c ] 呋喃。还进行了光物理和 DFT 计算,表明获得的 Indeno[1,2- c]呋喃表现出有前途的电子和光学特性。
Synthesis of Isocoumarins: Rhenium Complex-Catalyzed Cyclization of 2-Ethynylbenzoic Acids
When 2-ethynylbenzoic acids were treated with a catalytic amount of a rhenium complex, such as ReCl(CO())5, 6-endo cyclization of 2-ethynylbenzoic acids proceeded with a high selectivity to give the corresponding isocoumarins in moderate to good yields.