Hierarchical Beta zeolites as catalysts in a one-pot three-component cascade Prins–Friedel–Crafts reaction

Abstract

Hierarchical Beta zeolites obtained from concentrated reaction mixtures (H2O/Si = 2.5 – 7.0) with CTAB and their conventional and nanosponge analogues were investigated in a one-pot cascade environmentally friendly Prins–Friedel–Crafts...

MWW-type zeolite nanostructures for a one-pot three-component Prins–Friedel–Crafts reaction

“…A hierarchical beta zeolite ( H-beta-1 ) was synthesized via hydrothermal treatment of a concentrated RM (H 2 O/Si = 5.5, Si/Al = 25) according to the protocol described in ref. 20. Another hierarchical beta zeolite ( H-beta-2 , Si/Al = 15) was also synthesized in the presence of the multi–quaternary ammonium surfactant [C 22 -6Npipe-C 22 ](OH − ) 6 according to the technique given in ref.…”

“…, p -toluenesulfonic acid, trifluoromethanesulfonic acid) acid catalysts have been active in the one-pot Prins–Friedel–Crafts reaction, 5,12,19 however, the use of these catalysts is associated with environmental and economic issues, such as corrosion, toxic waste, laborious catalyst separation and regeneration. In contrast, environmentally benign montmorillonite K10 clay 13,14 and hierarchical beta zeolites 20 have been tested as heterogeneous catalysts in this reaction. Using K10 clay, the targeted product with a 4-aryltetrahydropyran moiety have been obtained in 75–91% yield, however, the reported synthesis protocol involves the use of carcinogenic and toxic chemicals (benzene and methanol).…”

“…13,14 Hierarchical zeolites consisting of beta nanoparticles provided up to 58% yield of the targeted products (4-(2(4)-methoxyphenyl)-2-propyltetrahydropyrans) while showing 95% conversion of aldehyde and replacing the carcinogenic substance (benzene) with a green one (anisole) and avoiding toxic chemicals like methanol. 20…”

“…The selection of beta as the reference catalysts is motivated by their promising activity in the sequence of Prins and Friedel–Crafts reactions demonstrated earlier. 20…”

Cascade intramolecular Prins/Friedel–Crafts cyclization for the synthesis of 4-aryltetralin-2-ols and 5-aryltetrahydro-5H-benzo[7]annulen-7-ols

“…The cascade Prins/Friedel-Crafts reaction to form multiple chemical bonds in one operation has emerged as an atomeconomic and straightforward strategy for the construction of oxygen-containing heterocycles [10][11][12][13][14]. For example, Nagumo and coworkers have developed a Prins/Friedel-Crafts cyclization of homocinnamyl alcohols with aromatic aldehydes under the action of BF 3 •Et 2 O affording 2H-indeno [1,2-b]furan deriva-tives [15].…”