Zuo Zhijun, Daniliuc Constantin G, Studer Armido
Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149, Münster, Germany.
Angew Chem Int Ed Engl. 2021 Nov 22;60(48):25252-25257. doi: 10.1002/anie.202110304. Epub 2021 Oct 25.
Cyclopropanes are an important class of building blocks in organic synthesis. Herein, a ring-opening/arylcarboxylation/acylation cascade reaction for the 1,3-difunctionalization of aryl cyclopropanes enabled by cooperative NHC and organophotoredox catalysis is reported. The cascade works on monosubstituted cyclopropanes that are in contrast to the heavily investigated donor-acceptor cyclopropanes more challenging to be difunctionalized. The key step is a radical/radical cross coupling of a benzylic radical generated in the photoredox catalysis cycle with a ketyl radical from the NHC catalysis cycle. The transformation features metal-free reaction conditions and tolerates a diverse range of functionalities.
环丙烷是有机合成中一类重要的结构单元。本文报道了一种由氮杂环卡宾（NHC）和有机光氧化还原催化协同实现的芳基环丙烷1,3-双官能化的开环/芳基羧基化/酰化串联反应。该串联反应适用于单取代环丙烷，与研究较多的给体-受体环丙烷相比，单取代环丙烷的双官能化更具挑战性。关键步骤是光氧化还原催化循环中产生的苄基自由基与NHC催化循环中产生的酮基自由基之间的自由基/自由基交叉偶联。该转化具有无金属反应条件，并且能耐受多种官能团。
