BF<sub>3</sub>·Et<sub>2</sub>O-Catalyzed Direct Carbon−Carbon Bond Formation of α-EWG Ketene-(<i>S</i>,<i>S</i>)-Acetals and Alcohols and Synthesis of Unsymmetrical Biaryls
作者:Qian Zhang、Shaoguang Sun、Jianglei Hu、Qun Liu、Jing Tan
DOI:10.1021/jo061775e
日期:2007.1.1
efficient BF3·OEt2-catalyzed formal dehydration C−C coupling reaction between readily available α-EWG ketene-(S,S)-acetals and various alcohols via direct substitution of the hydroxy group in alcohols has been developed. On the basis of this C−C coupling reaction, a series of alkylated α-EWG ketene-(S,S)-acetals and functionalized 1,4-pentanedienes were prepared in high to excellent yields and the unsymmetrical
Unexpected Hydrobromic Acid-Catalyzed CC Bond-Forming Reactions and Facile Synthesis of Coumarins and Benzofurans Based on Ketene Dithioacetals
作者:Hongjuan Yuan、Mang Wang、Yingjie Liu、Lili Wang、Jun Liu、Qun Liu
DOI:10.1002/chem.201002107
日期:2010.12.3
Hydrobromic acid was found to be a unique catalyst in CC bond‐forming reactions with ketene dithioacetals. Distinctly different from other acids (including Lewis and Brønsted acids), the remarkable catalytic performance of hydrobromic acid in catalytic amounts was observed in the “acid”‐catalyzed reactions of readily available functionalized ketene dithioacetals 1 with various electrophiles. Under
氢溴酸被发现是在C独特催化剂与烯酮二硫C键形成反应。与其他酸(包括路易斯酸和布朗斯台德酸)明显不同,氢溴酸在催化量上的显着催化性能在易于获得的官能化乙烯酮二硫缩醛1与各种亲电试剂的“酸”催化反应中观察到。在0.1当量的氢溴酸的催化下,1与羰基化合物2 a – l的反应生成多官能化的戊-1,4-二烯3或共轭二烯4产量高到极好。该反应在乙烯酮二硫缩醛1和羰基化合物2上均具有宽范围的取代基。这种有效的CC键形成方法的应用是在温和的,无金属的条件下,通过氢溴酸1与水杨醛2 m - o和对苯醌6 a - d的反应生成香豆素5和苯并呋喃7。, 分别。根据抗衡离子的性质,形成了一种新的反应性物种,即一种硫稳定的碳鎓叶立德,这被提议作为氢溴酸独特催化的关键中间体。
Iron-catalyzed alkylation of α-oxo ketene dithioacetals
作者:Qin Yang、Ping Wu、Jiping Chen、Zhengkun Yu
DOI:10.1039/c4cc02264e
日期:——
Iron-catalyzed alkylation of α-oxo ketene dithioacetals by styrenes efficiently afforded highly functionalized tetrasubstituted olefins.
铁催化的α-氧酮二硫代醛与苯乙烯的烷基化反应高效地合成了高度官能化的四取代烯烃。
Alternative Palladium-Catalyzed Vinylic C−H Difluoroalkylation of Ketene Dithioacetals Using Bromodifluoroacetate Derivatives
作者:Shuangquan Tian、Xiaoning Song、Dongsheng Zhu、Mang Wang
DOI:10.1002/adsc.201701554
日期:2018.4.3
A palladium‐catalyzedcross‐coupling of α‐oxo ketene dithioacetals and bromodifluoroacetate derivatives has been developed for the synthesis of a class of CF2‐containing tetra‐substituted olefins, which has potential to extend to drug design and material application. The process is proposed to involve two single electron transfer processes accompanied by an alternative loop from palladium(0) to palladium(I)
Copper(II) Bromide/Boron Trifluoride Etherate-Cocatalyzed Cyclization of Ketene Dithioacetals and p-Quinones: a Mild and General Approach to Polyfunctionalized Benzofurans
作者:Yingjie Liu、Mang Wang、Hongjuan Yuan、Qun Liu
DOI:10.1002/adsc.200900809
日期:2010.3.22
general method for catalytic synthesis of polyfunctionalized benzofurans with the advantages of readily available starting materials, cheap catalysts, mild reaction conditions, good yields and wide range of synthetic potential for the benzofuran products. Further transformations of the resulting benzofurans to 2‐aminobenzofurans and benzofuro[2,3‐d]pyrimidine derivatives are also investigated.