Cyclodextrin‐supported palladium complex: A highly active and recoverable catalyst for Suzuki–Miyaura cross‐coupling reaction in aqueous medium

Abstract

A water‐soluble, cyclodextrin‐supported palladium complex (DACH‐Pd‐β‐CD) catalytic system was designed and synthesized, which can efficiently catalyze Suzuki–Miyaura cross‐coupling reactions between aryl halides and arylboronic acid in water under mild conditions. The catalyst was successfully characterized using the methods of transmission electron microscopy, energy‐dispersive X‐ray spectrometry, X‐ray diffraction, thermogravimetric analysis, and Fourier transform infrared and NMR spectroscopies. Furthermore, the catalyst can be easily separated from the reaction mixture and still maintain high catalytic activity after ten cycles. No leaching of palladium into the reaction solution occurred. The advantages of green solvent (water), short reaction times (2–6 h), low catalyst loading (0.001 mol%), excellent yields (up to 99%) and reusability of the catalyst mean it will have potential applications in green chemical synthesis.

Synthetic Application of Cyclodextrins in Combination with Metal Ions, Complexes, and Metal Particles

“…Catalyst 4.5 % Pd 0 -21-βCD prepared by the Yang group and tested in the reduction of nitrobenzenes (see Scheme 5) [62] was used in Suzuki coupling of iodo-and bromo-benzenes as well. [136] It showed high activity at low catalyst loading (76À 98 %; 0.001 mol %, Cs 2 O 3 , H 2 O, 80°C, 1-8 h). Hindered 2formylbromobenzene gave the lowest yield (65 %, 24 h).…”

Recent Progress in the Suzuki-Miyaura Cross-Coupling Reactions in Water

“…2016 年, 杨睿课题组 [31] 采用直接功能化 β-CD 的方 法, 即将氨基化的 β-CD 与 Pd(OAc) 2 络合, 成功制备了 一种新型催化剂 DAPH-Pd-β-CD (Scheme 17). 研究表 明该催化剂具有两大特点: 一方面, 在 80 ℃反应温度 同年, Pitchumani 课题组 [32] 2014 年, Giri 等 [44] 使用 CuI/2-P(t-Bu) 2 PhNMe 2 催化 剂在 DMF/1,4-二氧六环混合溶剂中进行 SMC 反应.由于 有机化学 综述与进展 存在催化活性弱(只能催化碘代芳烃)及难回收等缺陷, 因此, 人们对铜催化体系进行 SMC 的研究一直较少 [45] .…”

An Amino-Chain Modified β-cyclodextrin: A Supramolecular Ligand for Pd(OAc)2 Acceleration in Suzuki–Miyaura Coupling Reactions in Water

“…With these issues in mind, many catalytic systems have been developed using various carriers to immobilize Pd catalysts, for example silica [8], Pd/C [9], magnetic nanoparticles [10][11][12], carbon nanotubes [13], nanomaterials [14][15][16], polymers [17,18], and cyclodextrins [19]. Among the various carriers, cyclodextrins (CD) have recently attracted abundant attention for Suzuki-Miyaura coupling reactions, given that phosphine free CD ligands support Pd catalytic systems [20][21][22][23][24].…”