Photochemical O−H Functionalization Reactions of Cyclic Diazoamides
作者:Claire Empel、Dennis Verspeek、Sripati Jana、Rene M. Koenigs
DOI:10.1002/adsc.202000818
日期:2020.11.4
Herein, we describe the photochemical O−H functionalization reaction of acidic alcohols with cyclic diazoamides. We studied the O−H functionalization reaction of different fluorinated and non‐fluorinated alcohols to give the corresponding ether products in high yields (43 examples, up to 97% yield). Furthermore, we performed studies to evaluate a photoexcited proton transfer reaction pathway in comparison
Diastereoselective Synthesis of β-Lactam-Oxindole Hybrids Through a Three-Component Reaction of Azetidine-2,3-diones, α-Diazo-oxindoles, and Alcohols Catalyzed by [Rh2(OAc)4]
β-Lactam–oxindolehybrids have been synthesized in good yields in a one-pot procedure through efficient and stereoselective capture of an oxonium ylide with azetidine-2,3-diones. The reaction allows high to moderate control of stereoselectivity, depending on the 3-diazo-oxindole precursor and the hydroxylic compound used. Two new quaternary stereogenic centers were formed; the stereochemistry at the
通过用氮杂环丁烷-2,3-二酮有效和立体选择性地捕获氧鎓叶立德,已经在一锅法中以良好的产率合成了β-内酰胺-羟吲哚杂化物。根据所使用的 3-重氮-羟吲哚前体和羟基化合物,该反应允许对立体选择性进行高到中等控制。形成了两个新的四元立体中心;C-3 季中心的立体化学由 C-4 上的大取代基控制,而相邻的第二季立体中心的立体选择性由 α-重氮-羟吲哚控制。两个四元中心的立体化学已通过单晶 X 射线衍射明确指定。
Photoinduced Synthesis of Functionalized Oxacyclic Spirooxindoles Via Ring Expansion
A versatile photochemical ring-expansion protocol for the synthesis of oxacyclic spirooxindoles under catalyst-free conditions is described. The reaction is enabled by the use of unstrained O-containing heterocycles with 3-diazoindolin-2-ones under visible-light irradiation. Several synthetic advantages for this method are exhibited, including mild conditions, good functional group tolerance, operational
描述了在无催化剂条件下合成 oxacyclic spirooxindoles 的多功能光化学扩环协议。该反应是通过在可见光照射下使用未应变的含 O 杂环和 3-二氮并吲哚-2-酮来实现的。展示了该方法的几个合成优势,包括温和的条件、良好的官能团耐受性、操作简单性和可扩展性。机理研究表明,转化可能通过氧鎓叶立德中间体的形成,然后是离子环化来进行。