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。
Synthesis, rearrangements, and fragmentation of ketene mercaptals derived from ketones or β-diketones and carbon disulphide
作者:L. Dalgaard、L. Jensen、S.-O. Lawesson
DOI:10.1016/s0040-4020(01)97222-9
日期:1974.1
By use of the ion pair extraction technique, tetrabutylammonium salts of acetylacetone, benzoylacetone, and dibenzoylmethane were reacted with carbon disulphide to give salts of dithioacids. Alkylation gave dithioesters and ketene mercaptals. A simple procedure for the preparation of 2-diacylmethylene-1,3-dithietanes was found. Cyclisation reactions of some acetylacetone derivatives gave a 1,3-dithiolane
Synthesis of γ-Pyrones from Formal [4 + 2] Cyclization of Ketene Dithioacetals with Acyl Chlorides
作者:Mingshan Wang、Lou Shi、Yifei Li、Qun Liu、Ling Pan
DOI:10.1021/acs.joc.9b01254
日期:2019.8.2
been developed. Mediated by lithium bis(trimethylsilyl)amide, a series of γ-pyrones were obtained with a broad substrate scope. This unprecedented formal [4 + 2] cyclization provides a novel mode for ketene dithioacetals as versatile synthons. The synthesized γ-pyrones could be successfully transformed to 2-aryl/amino γ-pyrones and 2,3-dihydroimidazo[1,2-a]pyridin-7(1H)-ones mainly via the cleavage of
已开发出容易获得的乙烯酮二硫缩醛与酰氯的正式[4 + 2]环化反应。在双(三甲基甲硅烷基)酰胺锂的介导下,获得了一系列具有较宽底物范围的γ-吡喃酮。这种前所未有的形式化[4 + 2]环化为烯酮二硫缩醛作为通用合成子提供了一种新颖的模式。合成的γ-吡喃酮主要通过C–S键的裂解成功转化为2-芳基/氨基γ-吡喃酮和2,3-二氢咪唑并[1,2 - a ]吡啶-7(1 H)-酮。 。
Controlled Ring-Opening of Siloxydifluorocyclopropanes for Carbocyclization: Synthesis of Difluorocyclopentenones
作者:Xiaoning Song、Shuangquan Tian、Ziming Zhao、Dongsheng Zhu、Mang Wang
DOI:10.1021/acs.orglett.6b01567
日期:2016.7.15
A highly controlled ring opening of siloxydifluorocyclopropanes, formed by nBuN4Br-catalyzed difluorocyclopropanation of methyl vinyl ketones bearing a β-alkylthio group by using TMSCF2Br as a unique difluorocarbene source, results in metal difluorohomoenolates with assistance of copper or silver followed by an intramolecular addition and elimination reaction leading to α-gem-difluorocyclopentenones
Palladium-Catalyzed C–S Bond Cleavage with Allenoates: Synthesis of Tetrasubstituted 2-Alkenylfuran Derivatives
作者:Quannan Wang、Zhuqing Liu、Jiang Lou、Zhengkun Yu
DOI:10.1021/acs.orglett.8b02253
日期:2018.10.5
Palladium-catalyzed C–S cleavage of tetrasubstituted internal alkene α-oxo ketene dithioacetals was realized with allenoates as the coupling partners, efficiently affording tetrasubstituted 2-alkenylfuran derivatives with excellent regioselectivity under mild conditions. Allenoates acted as C1 synthons in the desulfurative [4 + 1] annulation.
An efficient protocol toward fully substitutedthiophenes and thieno[2,3-b]thiophenes has been developed through CuCl2-catalyzed annulative coupling of S,S-disubstituted enones with diazo compounds under mild conditions. Tetrasubstituted thiophenes and thieno[2,3-b]thiophenes were efficiently accessed by variation of the feed ratio of the reactants in good to excellent yields, respectively. The synthetic