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。
Visible-Light-Induced Sulfur-Alkenylation of Alkenes
作者:Qi Xu、Xiaoxuan Zhou、Si Zhang、Ling Pan、Qun Liu、Yifei Li
DOI:10.1021/acs.orglett.1c01596
日期:2021.6.18
proceed in a highly regio- and stereospecific manner involving the visible-light-induced conversion of a ketene dithioacetal to the thiavinyl 1,3-dipole intermediate, followed by a formal [3 + 2] cycloaddition and C–S bond cleavage. Furthermore, it is also an efficient approach for the late-stage functionalization of natural products and complex molecules, even being induced by sunlight under ambient
Iron(III) Chloride Promoted Desulfitative C–C Coupling Reaction of α-Oxo Ketene Dithioacetals and Indoles: Highly Selective Synthesis of β,β-Bisindolyl and β-Indolyl α,β-Unsaturated Carbonyl Compounds
作者:Haifeng Yu、Tiechun Li、Peiqiu Liao
DOI:10.1055/s-0032-1317691
日期:——
Abstract The iron(III) chloridepromoted desulfitative C–C coupling of α-oxo ketene dithioacetals with indoles was developed for the synthesis of indole derivatives. In the presence of iron(III) chloride, α-oxo ketene dithioacetals reacted efficiently and highly selectively with C2-unsubstituted or C2-substituted indoles to afford excellent yields of β,β-bisindolyl or β-indolyl α,β-unsaturated carbonyl
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。
2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)-Mediated C(<i>sp</i>
<sup>2</sup>
)-C(<i>sp</i>
<sup>3</sup>
) Cross-Dehydrogenative Coupling Reaction: α-Alkylation of Push-Pull Enamines and α-Oxo Ketene Dithioacetals
作者:Dongping Cheng、Lijun Wu、Zhiteng Deng、Xiaoliang Xu、Jizhong Yan
DOI:10.1002/adsc.201700853
日期:2017.12.19
A novel, metal‐free cross‐dehydrogenativecoupling (CDC) reaction of C(sp2)–H bonds of enamines and α‐oxo ketene dithioacetals with C(sp3)–H bonds of 1,3‐diarylpropenes mediated by 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) is reported. The α‐alkylation products are obtained with moderate to good yields. The method provides an efficient and alternative strategy for the synthesis of the corresponding