Barium based alginates in heterogeneous catalysis for Friedel Crafts enantioselective reaction

Alginate is a polysaccharide from brown algae and is available in almost unlimited quantities at very low prices. In the presence of divalent metals, these renewable biopolymers can readily form hydrogels, solvogel, and aerogels. Alginate beads can be used as chiral heterogeneous catalysts for enantioselective reactions. A representative reaction, the Friedel-Crafts alkylation of nitroolefins with indoles, was tested in this master's thesis. Having prepared previously optimized barium alginate beads prior to the study, this study tested new substrates involving the prevalence of nitroolefins and indoles in different nitroolefins, obtaining moderate yields and good enantiomeric excesses under optimized reaction conditions. The recyclability studies of barium alginate beads showed good stability and recyclability, with the same catalyst being used at least five times with similar results. The heterogeneity of the catalytic action was also demonstrated by the Sheldon test.