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

Abstract

A rhodium complex was immobilized for the first time in iota-carrageenan polysaccharide to render a xerogel catalyst. This new heterogeneous catalyst was successfully used in Suzuki cross-coupling and was easily separated from the reaction mixture and recycled two times without loss of activity. The rhodium heterogeneous catalyst was characterized by FTIR, SEM-EDS, and TEM analyses, which demonstrated that the catalyst complex successfully embedded within the polysaccharide and exhibited an unordered, porous structure. Moreover, it was demonstrated that the novel and simple heterogenization procedure, which has been used previously for palladium complexes, is a general route to immobilize transition metal complexes in polysaccharide matrixes.

Green Procedure for Aerobic Oxidation of Benzylic Alcohols with Palladium Supported on Iota-Carrageenan in Ethanol

“…Based on our previous work, iota (i) carrageenan was selected as the support for the heterogeneous system [38][39][40][41][42][43][44]. With this support, the reaction with i-Pd(OAc) 2 (TPPTS) 2 was superior to that with i-PdCl 2 (TPPTS) 2 (Table 1, entries 7 and 8).…”

“…Recently, we also proposed a simple and straightforward procedure to immobilize palladium complexes on various renewable polysaccharides by using sodium triphenylphosphine trisulfonate (TPPTS) as ligand and anchor. The new heterogeneous catalysts were successfully used in Suzuki cross-coupling [38][39][40][41][42] and Heck coupling and in the transfer hydrogenation of olefins [43,44].…”