Solvent effects on catalytic activity and selectivity in amine-catalyzed d-fructose isomerization
Solvent effects on catalytic activity and selectivity in amine-catalyzed d-fructose isomerization
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DOI：
10.1016/j.jcat.2022.12.029
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发表时间：
2022-12
影响因子：
7.3
通讯作者：
Peter Drabo;M. Fischer;Meike Emondts;Jegor Hamm;Mats Engelke;Marc Simonis;Long Qi;S. Scott
中科院分区：
文献类型：
--
作者：
Peter Drabo;M. Fischer;Meike Emondts;Jegor Hamm;Mats Engelke;Marc Simonis;Long Qi;S. Scott
合理的催化剂设计和最佳溶剂选择是推进生物精炼的关键。在这里，我们探讨了有机催化异构化的d-果糖，一个有价值的稀有单糖，d-阿洛酮糖，作为溶剂的功能。果糖异构化为阿洛酮糖与葡萄糖异构化和糖降解竞争。在水和DMF中，胺对果糖的催化活性与其碱性有关。溶剂通过改变d-果糖的互变异构体分布而显著影响选择性。结果表明，果糖的呋喃糖互变异构体被异构化为阿洛酮糖，异构体的丰度随水< MeOH < DMF> DMSO的增加而增加。在非质子溶剂中的反应速率也高于在质子溶剂中的反应速率。以1，5，7-三氮杂双环[4.4.0]癸-5-烯（TBD）为催化剂，在DMF中反应，阿洛酮糖的产率最高，为14%。利用核磁共振谱对反应动力学和机理进行了探讨。
Rational catalyst design and optimal solvent selection are key to advancing biorefining. Here, we explored the organocatalytic isomerization ofd-fructose to a valuable rare monosaccharide,d-allulose, as a function of solvent. The isomerization ofd-fructose tod-allulose competes with its isomerization tod-glucose and sugar degradation. In both water and DMF, the catalytic activity of amines towardsd-fructose is correlated with their basicity. Solvents impact the selectivity significantly by altering the tautomeric distribution ofd-fructose. Our results suggest that the furanose tautomer ofd-fructose is isomerized tod-allulose, and the fractional abundance of this tautomer increases as follows: water < MeOH < DMF ≈ DMSO. Reaction rates are also higher in aprotic than in protic solvents. The bestd-allulose yield, 14 %, was obtained in DMF with 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as the catalyst. The reaction kinetics and mechanism were explored usingoperandoNMR spectroscopy.