Photoredox-Catalyzed Decarboxylative Bromination, Chlorination and Thiocyanation Using Inorganic Salts
Photoredox-Catalyzed Decarboxylative Bromination, Chlorination and Thiocyanation Using Inorganic Salts
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使用无机盐进行光氧化还原催化脱羧溴化、氯化和硫氰化
DOI：
10.1002/ange.202309684
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发表时间：
2023
影响因子：
--
通讯作者：
Wu J
中科院分区：
文献类型：
--
作者：
Wu J
烷基羧酸的脱羧卤化反应对于合成结构多样的烷基卤化物是非常有价值的反应。然而，许多报道的方案依赖于化学计量的强氧化剂或高度亲电的卤化剂。在本文中，我们描述了N-羟基邻苯二甲酰亚胺活化的羧酸的可见光光氧化还原催化的脱羧卤化反应，其避免化学计量的氧化剂并使用廉价的无机卤化物盐作为卤化剂。在简单的、不含过渡金属的条件下，使用有机光氧化还原催化剂且不含其他添加剂，用溴化锂进行溴化反应，而用氯化锂进行氯化反应则需要双重光氧化还原-铜催化。温和的条件显示出优异的官能团耐受性，这通过将各种结构复杂的含羧酸的天然产物转化为相应的烷基溴和烷基氯来证明。此外，我们通过扩展到与硫氰酸钾的硫氰酸化，显示了与无机盐的双重光氧化还原-铜催化脱羧官能化的一般性，该方法被应用于合成复合硫氰酸烷基酯。
Decarboxylative halogenation reactions of alkyl carboxylic acids are highly valuable reactions for the synthesis of structurally diverse alkyl halides. However, many reported protocols rely on stoichiometric strong oxidants or highly electrophilic halogenating agents. Herein, we describe visible‐light photoredox‐catalyzed decarboxylative halogenation reactions ofN‐hydroxyphthalimide‐activated carboxylic acids that avoid stoichiometric oxidants and use inexpensive inorganic halide salts as the halogenating agents. Bromination with lithium bromide proceeds under simple, transition‐metal‐free conditions using an organic photoredox catalyst and no other additives, whereas dual photoredox‐copper catalysis is required for chlorination with lithium chloride. The mild conditions display excellent functional‐group tolerance, which is demonstrated through the transformation of a diverse range of structurally complex carboxylic acid containing natural products into the corresponding alkyl bromides and chlorides. In addition, we show the generality of the dual photoredox‐copper‐catalyzed decarboxylative functionalization with inorganic salts by extension to thiocyanation with potassium thiocyanide, which was applied to the synthesis of complex alkyl thiocyanates.