Selective Reduction of Carboxylic Acids to Alcohols in the Presence of Alcohols by a Dual Bulky Transition-Metal Complex/Lewis Acid Catalyst
Selective Reduction of Carboxylic Acids to Alcohols in the Presence of Alcohols by a Dual Bulky Transition-Metal Complex/Lewis Acid Catalyst
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DOI：
10.1021/acscatal.1c04392
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发表时间：
2022-01
期刊：
影响因子：
12.9
通讯作者：
Bendik Grømer;S. Yoshioka;S. Saito
中科院分区：
文献类型：
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作者：
Bendik Grømer;S. Yoshioka;S. Saito
：在这里，我们报告了一种普遍适用的一元和二元羧酸还原的分子方法，可选择性地提供多种醇，包括一元醇和二醇。羧酸直接氢化为醇的固有缺点之一是通过羧酸与生成的醇的缩合就地形成相应的酯。特别是，多元羧酸的氢化经常会因形成低聚酯的复杂混合物而受到影响。通过联合使用由大体积 (PNNP) 铱络合物和路易斯酸组成的双催化剂，成功解决了这个问题。由于铱催化剂的空间体积和稳定性，路易斯酸的主要作用是独立催化酯化反应，尽管似乎也暗示了路易斯酸对铱催化剂（静止状态）的协同活化。
: Here, we report a molecular method for the generally applicable reduction of mono- and dicarboxylic acids that selectively furnishes a diverse variety of alcohols, including mono- and diols. One of the inherent drawbacks of the direct hydrogenation of carboxylic acids to alcohols is the in situ formation of the corresponding esters via condensation of the carboxylic acids with the produced alcohols. Especially, the hydrogenation of polycarboxylic acids frequently su ff ers from the formation of a complex mixture of oligomeric esters. This issue was successfully overcome by the combined use of a dual catalyst that consists of a bulky (PNNP)iridium complex and a Lewis acid. Owing to the steric bulk and robustness of the iridium catalyst, the main role of the Lewis acid is to independently catalyze the esteri fi cation, albeit the cooperative activation of (a resting state of) the iridium catalyst by the Lewis acid also seems to be implied.