Visible-light-induced N-heterocyclic carbene mediated cascade transformation of N-alkenoxypyridinium salts
Visible-light-induced N-heterocyclic carbene mediated cascade transformation of N-alkenoxypyridinium salts
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DOI：
10.1016/j.cclet.2022.01.028
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发表时间：
2022-01
影响因子：
9.1
通讯作者：
He Sheng;Qiang Liu;Fei Chen;Zhixiang Wang;Xiangyu Chen
中科院分区：
文献类型：
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作者：
He Sheng;Qiang Liu;Fei Chen;Zhixiang Wang;Xiangyu Chen
虽然-烷氧基吡啶盐被广泛用于α功能化酮的合成，但这种方法通常仅限于高温下的特殊亲核剂。在这里，我们开发了一种替代的N-杂环卡宾(NHC)介导的N-烷氧基吡啶盐与不同的亲核试剂在温和的条件下功能化，包括四甲铵叠氮，仲胺，芳基和烷基硫醇，甚至挑战的C(SP3)-亲核试剂。提出了一种级联自由基-自由基偶联/亲核取代序列，其中NHC能够形成光活性电子供体-受体络合物，用于α-碘酮的合成。
WhileN-alkenoxypyridinium salts are widely used for the synthesis ofα-functionalized ketonesviaumpolung strategy, such approaches are usually limited to special nucleophiles at high temperatures. Herein, we developed an alternative photoinducedN-heterocyclic carbene (NHC)- mediated functionalization ofN-alkenoxypyridinium salts with various nucleophiles, including tetramethylammonium azide, secondary amines, aryl and alkyl thiols, and even the challenging C(sp3)-nucleophiles, under mild conditions. A cascade radical-radical coupling/nucleophilic substitution sequence was proposed, wherein the NHC enabled the formation of a photoactive electron donor-acceptor complex forα-iodo ketone synthesis.