“…46,50 Different organic transformations have been carried out via functionalized PC4RA as a catalyst in the last decade, such as an expansion of triarylthiopyrylium salts, 42 xanthenes, 43,51 quick [3+2] Huisgen cycloaddition, 52 benzyl azide synthesis, 53 oxidation of benzyl alcohol, 54 phthalazine triones, 55 and epoxide ring opening. 56 It is worth noting that polymers, in comparison with inorganic supports, have exhibited appreciable stability in acidic media, particularly porous polymers based on Cis-C4RA due to their cone-like cavities. Cavitands are composed of a fourfold aromatic ring enclosed by the hydrophilic group.…”