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

Abstract

A well-designed and synthesized water-soluble class of β-cyclodextrin supported palladium complex PdLn@Et-β-CD could efficiently validate high catalytic activity and act as a supramolecular platform for phosphine-free Suzuki–Miyaura cross‐coupling reactions between arylboronic acid/ arylboronic ester and aryl halides in water under mild conditions. The presented novel PdLn@Pr-β-CD complex catalyst was characterized by NMR, XRD, FT-IR, and DSC analysis. Furthermore, the role of the PdLn@Et-β-CD fragment in the reaction mechanism studied by molecular complexation was proposed based on FT-IR, 2D NMR (ROESY) spectroscopy, FE-SEM, and DSC spectroscopic analysis. The important benefits of this technique comprise simple phosphine-free preparation of the palladium catalyst, a wide range of functional-group tolerance, and easy recyclability; this method, furthermore, eschews hazardous reagents or solvents.

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

“…[132] Tests in the Suzuki reaction of 4-bromobenzoic acid and phenylboronic acid showed high activity at room temperature [> 97 % yield; 0.5 mol % Pd 2 + complex and 2,6-diMeOβCD, Na 2 CO 3 , (2.4 equiv), Jung et al fabricated another Pd(OAc) 2 complex using βCD modified with ethylenediamine (59 c-βCD). [133] Successful synthesis was indicated by 1 Hexagonal boron nitride (h-BN) nanosheets with anchored βCD served as solid support material to form a complex with Pd(OAc) 2 . [134] According to SEM analysis, the nanosheets after Pd loading were broken and aggregated (particles of 50-500 nm).…”

Heterogeneous Supported Palladium Catalysts for Liquid‐Phase Allylation of Nucleophiles

“…[8] In recent years, many efforts have been made to develop solid-supported transition metal complexes for use in the organic reaction catalysis. Supported palladium complexes, especially polymer resins and silicas, have proven useful for catalytic CÀ C bond formation reactions such as Suzuki-Miyaura coupling [9][10][11][12][13][14][15][16][17][18][19] and Heck cross-coupling. [12,14b,16,20-22] Unlike homogeneous palladium complex catalysts, heterogeneous solidsupported palladium catalysts are promising for their reusability and separability.…”

Synthesis of Mono- and Bis-Pyrazoles Bearing Flexible p-Tolyl Ether and Rigid Xanthene Backbones, and Their Potential as Ligands in the Pd-Catalysed Suzuki–Miyaura Cross-Coupling Reaction

“…Transition metal complexes of phosphorous (P), nitrogen (N), sulphur (S), and oxygen (O)-based ligands and their hybrids have provided chemists with a wide opportunity and a quasi-exhaustive tool for creating C-C bonds of significant interest [1,2]. The reactivity and the catalytic behaviour of these complexes largely depend on the nature of the coordinating atoms, their relative position within the molecular architecture, and the relative flexibility or rigidity of the ligand backbone, as they greatly influence steric and electronic properties of the resulting complex [3,4].…”