Sulfoxylate Anion Radical-Induced Aryl Radical Generation and Intramolecular Arylation for the Synthesis of Biarylsultams
Sulfoxylate Anion Radical-Induced Aryl Radical Generation and Intramolecular Arylation for the Synthesis of Biarylsultams
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DOI：
10.1021/acs.joc.1c03031
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发表时间：
2022-03-18
影响因子：
3.6
通讯作者：
Gupta, Pankaj
中科院分区：
文献类型：
--
作者：
Laha, Joydev K.;Gupta, Pankaj
使用电子供体从相应的芳基卤化物产生芳基自由基并随后与芳烃分子内环化可能是当代联芳基合成的重要进展。本文报道了一种绿色和实际有用的合成方案，以获得不同的六元和七元联芳基磺酰胺，特别是具有游离NH基团，包括克级合成的证明。从试剂保险粉或连二亚硫酸钠（Na 2S 2 O 4）原位产生的次硫酸根阴离子自由基（SO2-中心点）被发现是从芳基卤化物形成芳基自由基的关键单电子转移剂，其在分子内芳基化后以良好至优异的产率得到联芳基磺内酰胺。该方法的特点是产生的芳基自由基，仍然探索，使用廉价和容易获得的工业试剂，和过渡金属，温和的，和绿色的反应条件。
Aryl radical generation from the corresponding aryl halides using an electron donor and subsequent intramolecular cyclization with arenes could be an important advancement in contemporary biaryl synthesis. A green and practically useful synthetic protocol to access diverse six- and seven-membered biarylsultams especially with a free NH group including demonstration of a gram-scale synthesis is reported herein. The sulfoxylate anion radical (SO2-center dot), generated in situ from the reagents rongalite or sodium dithionite (Na2S2O4), was found to be the key single electron transfer agent forming aryl radicals from aryl halides, which upon intramolecular arylation gives biarylsultams with good to excellent yields. The approach features generation of aryl radicals that remained underexplored, use of a cheap and readily available industrial reagents, and transition metal-free, mild, and green reaction conditions.