Su Jiaqi, Shu Siwei, Li Yinwu, Chen Yong, Dong Jinxiang, Liu Yan, Fang Yanxiong, Ke Zhuofeng
School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, China.
PCFM Lab, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou, China.
Front Chem. 2022 May 10;10:897828. doi: 10.3389/fchem.2022.897828. eCollection 2022.
To understand the unprecedented difference between and selectivity in hypervalent iodine (III) promoted fluorocyclization of unsaturated carboxylic acids or alcohols by difluoroiodotoluene, density functional theory (DFT) studies have been performed to systematically compare both the previous proposed "fluorination first and cyclization later" mechanism and the alternative "cyclization first and fluorination later" mechanism. Our results revealed that the selectivity is mechanism-dependent. The unsaturated alcohol prefers the fluorination first and the cyclization later pathway, leading to the experimentally observed ether product. In contrast, the unsaturated carboxylic acid plausibly undergoes the cyclization first and the fluorination later to the experimentally observed lactone product. The p property of the functional group of the substrate is found to play a key role in determining the reaction mechanism. The provided insights into the mechanism-dependent selectivity should help advance the development of fluorocyclization reactions with hypervalent iodine reagents.
为了理解在高价碘（III）促进的不饱和羧酸或醇与二氟碘甲苯的氟环化反应中，[具体两种情况未给出]选择性之间前所未有的差异，我们进行了密度泛函理论（DFT）研究，以系统地比较先前提出的“先氟化后环化”机制和另一种“先环化后氟化”机制。我们的结果表明，选择性取决于反应机制。不饱和醇更倾向于先氟化后环化的途径，从而生成实验观察到的[醚产物未明确写出]醚产物。相比之下，不饱和羧酸可能先进行[环化情况未明确写出]环化，然后氟化生成实验观察到的[内酯产物未明确写出]内酯产物。发现底物官能团的p[具体性质未明确]性质在决定反应机制中起关键作用。对依赖于机制的选择性的深入了解应有助于推动使用高价碘试剂的氟环化反应的发展。
