A new thioglycolic ester β-cyclodextrin/PdCl2 in water: An accessible catalyst for the Suzuki-Miyaura coupling reaction

A novel, easily prepared and accessible water-soluble supramolecular catalyst for the Suzuki-Miyaura C-C coupling reaction was synthesized and characterized by FTIR, NMR, XRD, SEM, and HR-TEM. An inexpensive Pd (II) source added to the resulting aqueous solution of thioglycolic ester beta-cyclodextrin (1-TGA-SH-beta-CD/PdCl2) showed Pd nanoclusters and efficient catalytic activity for Suzuki-Miyaura C-C coupling reactions of aryl ha-lides with aryl boronic acids, employing K2CO3 as base, in an environmentally benign aqueous solution prepared in open flasks. Organic aryl halides including chlorides can produce moderate to excellent yields with aryl boronic acids and a small catalytic amount (0.01 mol%) of 1-TGA-SH-beta-CD/PdCl2. This hydro-soluble catalyst stock solution was stable for long periods (more than three months) and could be reused in two runs until showing loss of catalytic activity. Some experiments to understand the mechanism were performed, with the results suggesting incorporation of aryl halide in the catalytic cavity.

Automated summary

A novel water-soluble supramolecular catalyst for Suzuki-Miyaura C-C coupling reaction was synthesized and characterized. The catalyst exhibited efficient catalytic activity in an environmentally friendly aqueous solution and could be reused multiple times.