Zeolite-Directed Cascade Reactions:  Cycliacyarylation versus Decarboxyarylation of α,β-Unsaturated Carboxylic Acids

Abstract

The interaction of alpha,beta-unsaturated carboxylic acids with benzene derivatives was investigated in H-zeolites and led to two distinct but competing processes, cycliacyarylation and decarboxyarylation. Interestingly, H-USY selectively induced the cycliacyarylation cascade reaction, whereas H-ZSM5 selectively promoted the decarboxyarylation cascade.

Copper(I) Zeolites as Heterogeneous and Ligand‐Free Catalysts: [3+2] Cycloaddition of Azomethine Imines

“…This zeolite was selected first, since it proved efficient for several other reactions [12,13] and its large pores can accommodate several molecules.…”

“…In this context and in connection with our current studies on zeolites as catalysts in organic synthesis, [12,13] we explored the cycloaddition of azomethine imines derived from pyrazolidinones in the presence of copper(I) zeolites. We report here that copper(I) zeolites indeed act as ligand-free catalysts for the cycloaddition of azomethine imines and we detail here the scope of this first zeolite-catalyzed cycloaddition of azomethine imines [Scheme 2, Eq.…”

“Click Chemistry” in Zeolites: Copper(I) Zeolites as New Heterogeneous and Ligand‐Free Catalysts for the Huisgen [3+2] Cycloaddition

“…As click chemistry mediated by a source of heterogeneous copper(I) is very rare, [21,22,24] we looked for such catalysts and focused on zeolites in connection with our interest in solid acid-catalyzed chemistry, as well as in superacid-mediated organic transformations. [25] In this context, copper(I)-modified zeolites attracted our attention, these solid materials having been recently described and characterized but surprisingly never used for organic transformations. [26] In continuation of our preliminary results, [27] herein we report in more detail the scope and limitations of this first click chemistry in zeolites, as well as some evidence for the mechanism of this copper(I)-zeolite-catalyzed Huisgen reaction (Scheme 1).…”

BTISA-catalyzed Friedel–Crafts bimolecular cyclization of cinnamic acid under superelectrophilic solvation conditions

“…Initially we decided to study the reactivity of cinnamic acid as model substrate. Previously, this type of reactions was investigated using aluminium chloride [7], microwave-assisted/aluminium chloride [8], polyphosphoric acid [9], H-zeolites [10], and TFA/TFSA systems [11]. As far as could be determined, good yields of indanone were obtained under superelectrophilic solvation only requiring great excess of triflic acid (50-100 equiv.…”