Guzman Alexander L, Mann Alexis N, Hoye Thomas R
Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, United States.
J Am Chem Soc. 2024 Oct 23;146(42):28642-28647. doi: 10.1021/jacs.4c10897. Epub 2024 Oct 9.
Carbenes and carbenoids are commonly employed for the synthesis of cyclopropane-containing compounds. Here we report the metal-free, intramolecular cyclopropanation of tethered alkenes by free carbenes derived from alkynes to construct structurally unique multicyclic cyclopropanes with perfect atom economy. The nature of the tether influences both the rate of carbene formation and subsequent competing reaction events. Some of the substrates lead to metastable cyclopropane intermediates that further fragment to furnish interesting isomeric products by mechanistically novel processes. A removable siloxane tether can be utilized to achieve formal molecular cyclopropanations and to access cyclopropanol derivatives.
卡宾和类卡宾常用于含环丙烷化合物的合成。在此，我们报道了通过炔烃衍生的游离卡宾对连接烯烃进行无金属分子内环丙烷化反应，以构建具有完美原子经济性的结构独特的多环环丙烷。连接基团的性质既影响卡宾形成的速率，也影响随后的竞争反应过程。一些底物会生成亚稳态环丙烷中间体，这些中间体通过机制新颖的过程进一步碎片化，从而提供有趣的异构体产物。可除去的硅氧烷连接基团可用于实现形式上的分子环丙烷化反应，并获得环丙醇衍生物。
