Transition metal-free diastereospecific synthesis of (Z)-2-arylidene-2,3-dihydrobenzo[b][1,4]dioxines by reaction of (Z)-1,2-dibromo-3-aryl-2-propenes with catechols
作者:Szymon P. Rekowski、Aabid A. Wani、Jürgen Conrad、Prasad V. Bharatam、Wolfgang Frey、Uwe Beifuss
DOI:10.1016/j.tet.2020.131482
日期:2020.10
A transition metal-free, diastereospecific reaction between substituted (Z)-1,2-dibromo-3-phenyl-2-propenes and substitutedcatechols using Cs2CO3 as a base at 140 °C for 18 h delivers exclusively substituted (Z)-2-arylidene-2,3-dihydrobenzo[b][1,4]dioxines in yields up to 89%. Experiments as well as quantum chemical calculations support the assumption that the one pot transformation proceeds as an
在140°C下以Cs 2 CO 3为碱在取代的(Z)-1,2-二溴-3-苯基-2-丙烯与取代的邻苯二酚之间进行的无过渡金属非对映异构反应可产生仅被取代的(Z)-2-亚芳基-2,3-二氢苯并[ b ] [1,4]二恶英的产率高达89%。实验以及量子化学计算均支持以下假设:一锅转化以分子间O-烯丙基化/分子内O-乙烯基化的方式进行。
Competitive, substrate-dependent reductive debromination/dehydrobromination of 1,2-dibromides with triethylamine
作者:Kristen M. McGraw、Greggory T. Kent、Joseph R. Gonzalez、Ihsan Erden、Weiming Wu
DOI:10.1016/j.tetlet.2017.04.024
日期:2017.5
various 1,2-dibromides with NEt3 under various conditions (THF and DMF, respectively) at different temperatures was investigated. Our results from these reactions show that substrate dependent dehydrobrominations compete with reductive debrominations. A comprehensive discussion of these competitive pathways is offered.
Simple and Efficient Copper-Catalyzed Approach to 2,4-Disubstituted Imidazolones
作者:Xiaoyu Gong、Haijun Yang、Hongxia Liu、Yuyang Jiang、Yufen Zhao、Hua Fu
DOI:10.1021/ol1008813
日期:2010.7.16
Some imidazolone derivatives are biological and pharmaceutical active molecules and the chromophores of the fluorescent proteins. In this communication, a simple and efficient approach to 4-arylidene-2-alkyl-4,5-dihydro-1H-imidazol-5-ones (2,4-disubstituted imidazolones) has been developed, and the protocol uses readily available 2-bromo-3-alkylacrylic acids and amidines as the starting materials without addition of any ligand or additive. The reactions were performed under mild conditions. Therefore, the present method will be of wide application in organic chemistry and medicinal chemistry.
A New Method for the Synthesis of 2,6-Disubstituted 4(3<i>H</i>)-Pyrimidinones from Benzamidine