Study of Pd-based catalysts within red algae-derived polysaccharide supports in a Suzuki cross-coupling reaction

Abstract

Simple palladium complexes were heterogenized into red algae derived polysaccharide supports, and the effects of polysaccharide, catalyst and solvent types on the performances in a Suzuki cross-coupling reaction were tested.

RhCl(TPPTS)3 supported on iota‐carrageenan as recyclable catalysts for Suzuki cross‐coupling

“…As it involves polar and apolar organic substrates, an inorganic base and a metal catalyst, Suzuki cross‐coupling reactions are traditionally performed in polar solvents, such as dimethylformamide (DMF), dimethyl sulfoxide (DMSO) or various alcohols. We previously found that ethanol provided the most favorable conditions and was the most environmentally preferred solvent for Suzuki cross‐coupling with PdCl 2 (TPPTS) 2 or Pd(OAc) 2 (TPPTS) 2 immobilized on different polysaccharides . Thus, ethanol was also used as the solvent of choice for the reaction run with rhodium catalysts in this study.…”

“…The higher activity observed for the heterogeneous ἰ‐ PdCl 2 (TPPTS) 2 catalyst compared to the homogeneous PdCl 2 (TPPTS) 2 complex (Table , entries 3 and 4) has been suggested to be due to the presence of hydroxyl groups on the polymer backbone. Insofar as they create more polar and protic conditions, the hydroxyl groups conferred higher solubility in both the phenylboronic acid and the potassium carbonate in the respective reaction mixtures . Indeed, the addition of water or of an aqueous solution of i to the reaction mixture with PdCl 2 in ethanol resulted in higher conversions (Table , entries 5 and 6).…”

“…We recently published a novel method for the preparation of a polysaccharide‐based heterogeneous catalyst using palladium chloride or acetate with sodium triphenylphosphine trisulfonate as the ligand . Various renewable polysaccharides, and especially carrageenans, which are extracted from red seaweeds, were employed.…”

Recent Developments in the Immobilization of Palladium Complexes on Renewable Polysaccharides for Suzuki–Miyaura Cross-Coupling of Halobenzenes and Phenylboronic Acids

“…The Suzuki cross-coupling of several halobenzenes with phenylboronic acids was performed with the iota-based catalyst and yielded conversions from 15% to 77% after 24 h, and the catalyst iota-Pd(OAc)2(TPPTS)2 was successfully recycled four times, over the course of which the conversion decreased from 77% in the first run to 60% in the fifth run, and no catalyst leaching was detected [116]. FTIR spectra of the new catalyst indicated that a new C-O bond of Cell-OPPh 3 was synthesized.…”

“…The research group of Wolfson and Levy-Ontman reported on the synthesis of palladium-based catalysts within renewable polysaccharide supports by using different anchoring [115][116][117]. The catalysts were prepared in two steps: (1) add an aqueous solution of Pd(OAc) 2 (TPPTS) 2 or PdCl 2 (TPPTS) 2 , which was prepared from the corresponding palladium salt and the ligand (TPPTS = sodium triphenylphosphine trisulfonate ligand), to an aqueous solution of the polymer.…”