Dehydrative C–H Alkylation and Alkenylation of Phenols with Alcohols: Expedient Synthesis for Substituted Phenols and Benzofurans
作者:Dong-Hwan Lee、Ki-Hyeok Kwon、Chae S. Yi
DOI:10.1021/ja302710v
日期:2012.5.2
well-defined cationic Ru-H complex catalyzes the dehydrative C-H alkylation reaction of phenols with alcohols to form ortho-substituted phenol products. Benzofuran derivatives are efficiently synthesized from the dehydrative C-H alkenylation and annulation reaction of phenols with 1,2-diols. The catalytic C-H coupling method employs cheaply available phenols and alcohols, exhibits a broad substrate scope, tolerates
Synthesis of benzofurans from the cyclodehydration of α-phenoxy ketones mediated by Eaton’s reagent
作者:Zhanwei Ma、Min Zhou、Lin Ma、Min Zhang
DOI:10.1177/1747519820907244
日期:2020.7
acid) is used to prepare 3-substituted or 2,3-disubstituted benzofurans with moderate to excellent yields under mild conditions. The method provides a facile access to benzofurans from readily available starting materials such as phenols and α-bromo ketones. The reaction is highly efficient, which is attributed to the good reactivity and fluidity of Eaton’s reagent. The reaction can be applied to prepare
Rearrangement reactions of cycloalkenyl phenol and naphthyl ethers and the acid-catalyzed cyclization of the resulting product were investigated. Claisen rearrangement afforded 2-substituted phenol and naphthol derivatives. Combined Claisen and Cope rearrangement resulted in the formation of 4-substituted phenol and naphthol derivatives. In the case of cycloocthylphenyl ether the consecutive Claisen
Matrix metalloproteinase inhibitors are tricyclicsulfonamides of the Formula I
or a pharmaceutically acceptable salt thereof,
wherein R1 and R2 include hydrogen, alkyl, and substituted alkyl; R3 is OH or NHOH; X is O or S(O)n; n is 0, 1, or 2; p is 0, 1, 2, or 3; --- is absent or a bond; and the sulfur atom bearing (O)q is bonded to the benzo ring at position a or position b.
Ring Transformation of Annulated Benzofuran Derivatives to Medium-Sized Lactones
作者:Jens Christoffers、Lukas Fliegel、Julian Krauß
DOI:10.1055/a-2192-4044
日期:——
Benzannulated eight- and nine-membered-ring lactones were prepared by ringtransformation of annulated benzofuran derivatives. The reaction sequence starts with a Brønsted acid catalyzed hydration of the enol ether moiety of the starting materials furnishing hemiacetals as intermediate products which underwent retro-Claisen-type C–C bond cleavage under the reaction conditions. The use of 15 mol% TfOH
通过环状苯并呋喃衍生物的环转化制备了苯并八元环和九元环内酯。该反应顺序以布朗斯台德酸催化起始原料的烯醇醚部分的水合开始,提供半缩醛作为中间产物,该半缩醛在反应条件下经历逆克莱森型C-C键断裂。事实证明,在 85 °C 的 CHCl 3中使用 15 mol% TfOH 和两当量的水是最佳的。具有环外羧酸酯功能的产物可以通过酰胺形成进一步衍生化。总共制备了十一种中等大小的内酯。此外,从具有环外甲酰胺部分的起始材料获得了三种苯环化螺内酯。