The synthesis of adipic acid from sustainable biomass derived substrates under mild conditions is an important research area in green chemistry. Here, an innovative heterogeneous photocatalytic system was reported to prepare diethyl adipate (yield: 85% and apparent quantum efficiency: 12.9%) by dehalogenative CC homocoupling of glycerol-derived ethyl 3-iodopropionate using Ag/TiO2 as catalyst with base (cesium carbonate) as additive. The Ag/TiO2 catalyst has good stability and it shows excellent substrate universality for various halogenoalkane derivatives of industrial importance, such as diesters, diethers, dienes etc. DFT calculation revealed that Ag metal exhibited weak adsorption to H radical, which is beneficial to the selective formation of coupling products. Besides, cesium carbonate can effectively inhibit catalyst poisoning and facilitate the reduction of CI bond. This work provides an environmentally benign route for adipic acid synthesis from glycerol derivative and a new catalytic strategy for dehalogenative CC homocoupling of halogenated compounds.

中文翻译：

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光脱卤 C-C 均偶联法从甘油衍生物制备己二酸：Ag 助催化剂与碱的协同效应


在温和条件下从可持续生物质衍生底物合成己二酸是绿色化学的一个重要研究领域。在这里，据报道，一种创新的异相光催化系统通过使用 Ag/TiO2 作为催化剂，以碱（碳酸铯）为添加剂，通过甘油衍生的 3-碘丙酸乙酯的脱卤 CC 同偶联制备己二酸二乙酯（产率：85%，表观量子效率：12.9%）。Ag/TiO2 催化剂具有良好的稳定性，对各种具有工业重要性的卤代烷烃衍生物，如二酯、二醚、二烯烃等表现出优异的底材通用性。DFT 计算表明，Ag 金属对 H 自由基的吸附较弱，有利于偶联产物的选择性形成。此外，碳酸铯可有效抑制催化剂中毒，促进 CI 键的还原。这项工作为甘油衍生物合成己二酸提供了一种环境良性的途径，并为卤代化合物的脱卤 CC 同偶联提供了一种新的催化策略。