化学
部分
戒指(化学)
苯并呋喃
酰胺
立体化学
烯醇
键裂
烯醇醚
乙醚
腙
羟醛反应
内酯
有机化学
催化作用
作者
Lukas Fliegel,Juergen Krauss,Jens Christoffers
出处
期刊:Synlett
[Georg Thieme Verlag KG]
日期:2023-10-16
摘要
Abstract Benzannulated eight- and nine-membered-ring lactones were prepared by ring transformation 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 and two equivalents of water in CHCl3 at 85 °C turned out to be optimal. Products with exocyclic carboxylate function could be further derivatized by amide formation. In total, eleven medium-sized lactones were prepared. Furthermore, three benzannulated spirolactones were obtained from starting materials with exocyclic carboxamide moiety.
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