Perez Kaitlyn A, Rogers Cameron R, Weiss Emily A
Department of Chemistry, Northwestern University, 2145 Sheridan Rd., Evanston, IL, 60208-3113, USA.
Angew Chem Int Ed Engl. 2020 Aug 10;59(33):14091-14095. doi: 10.1002/anie.202005074. Epub 2020 Jun 3.
This Communication describes the use of CuInS /ZnS quantum dots (QDs) as photocatalysts for the reductive deprotection of aryl sulfonyl-protected phenols. For a series of aryl sulfonates with electron-withdrawing substituents, the rate of deprotection for the corresponding phenyl aryl sulfonates increases with decreasing electrochemical potential for the two electron transfers within the catalytic cycle. The rate of deprotection for a substrate that contains a carboxylic acid, a known QD-binding group, is accelerated by more than a factor of ten from that expected from the electrochemical potential for the transformation, a result that suggests that formation of metastable electron donor-acceptor complexes provides a significant kinetic advantage. This deprotection method does not perturb the common NHBoc or toluenesulfonyl protecting groups and, as demonstrated with an estrone substrate, does not perturb proximate ketones, which are generally vulnerable to many chemical reduction methods used for this class of reactions.
本通讯描述了使用铜铟硫/硫化锌量子点（QDs）作为光催化剂用于芳基磺酰基保护的酚类的还原脱保护反应。对于一系列带有吸电子取代基的芳基磺酸盐，相应的苯基芳基磺酸盐的脱保护速率随着催化循环中两次电子转移的电化学势降低而增加。对于含有羧酸（一种已知的量子点结合基团）的底物，其脱保护速率比根据该转化的电化学势预期的速率加快了十多倍，这一结果表明亚稳电子供体-受体络合物的形成提供了显著的动力学优势。这种脱保护方法不会干扰常见的叔丁氧羰基（NHBoc）或甲苯磺酰基保护基团，并且如在雌酮底物中所证明的那样，不会干扰邻近的酮羰基，而酮羰基通常容易受到用于此类反应的许多化学还原方法的影响。
