Acta Chimica Sinica ›› 2021, Vol. 79 ›› Issue (11): 1394-1400.DOI: 10.6023/A21080358 Previous Articles     Next Articles



张丹琪, 邵英博, 郑汉良, 周碧莹, 薛小松*()   

  1. 南开大学元素有机化学国家重点实验室 化学学院 天津 300071
  • 投稿日期:2021-08-01 发布日期:2021-09-10
  • 通讯作者: 薛小松
  • 基金资助:
    项目受国家自然科学基金(21933004); 项目受国家自然科学基金(21772098); 中央高校基本科研业务费专项资金资助

Mechanistic Study on the Bidentate Nitrogen-Ligated Iodine(V) Reagent Promoted Oxidative Dearomatization of Phenols

Danqi Zhang, Yingbo Shao, Hanliang Zheng, Biying Zhou, Xiao-Song Xue()   

  1. State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
  • Received:2021-08-01 Published:2021-09-10
  • Contact: Xiao-Song Xue
  • Supported by:
    National Natural Science Foundation of China(21933004); National Natural Science Foundation of China(21772098); Fundamental Research Funds for the Central Universities

Hypervalent iodine reagents, as a type of environmentally friendly and economical oxidants, have received extensive attention from synthetic chemistry in recent years. There are two kinds of common hypervalent iodine reagents: iodine(III) and iodine(V) reagents. Among various iodine(V) based reagents, 2-iodoxybenzoic acid (IBX) is one of the most commonly used oxidants in organic chemistry and has been widely used in selective oxidation of phenols, alcohols, thioethers and many other compounds. Although the IBX can efficiently oxidize electron-rich phenols to obtain o-quinones, which have important applications in catalysis and materials science, the synthesis of electron-deficient o-quinones is still challenging and remains an unsolved problem. Recently, a novel bidentate nitrogen-ligated iodine(V) reagent has been found to efficiently and selectively promote the oxidative dearomatization of electron-deficient phenols to o-quinones. The bidentate-nitrogen ligand has been demonstrated to play a crucial role in the successful oxidative dearomatization of electron-deficient phenols. To understand the origin of the effect of bidentate-nitrogen ligand on oxidative dearomatization, we herein conducted a detailed mechanistic study on the oxidative dearomatization of phenols promoted by iodine(V) reagents with different ligands by using density functional theory (DFT). Geometry optimizations and frequency calculations were carried out at the M06-2X/[6-31G(d,p)+LANL2DZ(I)] level of theory. To obtain more accurate electronic energies, single-point energy were calculated at the M06-2X/[6-311+G(2d,p)+def2-TZVPP(I)] level of theory. The solvation model based on density (SMD) was used to account for the solvation effect of chloroform, the solvents used in the experiment. Calculations revealed that the bidentate-nitrogen ligand not only enhances the reactivity of iodine(V) reagent but also acts as a base to neutralize the strong acid generated in the reaction to prevent product degradation. The insights into the effect of the bidentate-nitrogen ligand on the reactivity of hypervalent iodine reagent obtained from this study would facilitate the future design of novel ligand- regulated hypervalent iodine reagents for new reactions.

Key words: bidentate-nitrogen ligand, iodine(V) reagent, oxidative dearomatization, o-quinone, DFT calculation