Sc^III‐Doped Zeolites as New Heterogeneous Catalysts: Mukaiyama Aldol Reaction

Abstract

Sc(III)-doped solids based on zeolite materials have been investigated for the first time as catalysts in organic synthesis. Sc(III)-USY zeolite proved to be a novel and very efficient heterogeneous catalyst for the Mukaiyama aldol reaction. This easy-to-prepare catalyst exhibited wide scope and compatibility with functional groups and is very simple to use, easy to remove (by simple filtration), and is recyclable (up to three times without loss of activity).

Metal-doped Zeolites as Green Catalysts for Organic Synthesis

“…We thus first examined the behavior of Sc III zeolites in this reaction with various silyl enolethers and aldehydes (Scheme 7) [30].…”

Scandium(III) Zeolites as New Heterogeneous Catalysts: [4+2]Cyclocondensation of in situ Generated Aryl Imines with Alkenes

“…[35] Organic reactions performed in zeolites could occur with mechanisms similar or different from the same reaction in homogeneous conditions, as observed for Cu I -zeolite-catalyzed reactions. [25][26][27][28] The present Sc III -zeolite-catalyzed cyclocondensations could thus follow either normal or reverse electron demand Diels-Alder pathways or a stepwise cationic route, or both of them.…”

“…On the other hand, we also recently showed that Sc III zeolites are useful and reusable catalysts for Mukaiyama-type aldolizations (Scheme 3d). [28] Lanthanide and Sc III salts are known to promote hetero-DielsAlder reactions. [29] Thus, Sc III zeolites seem good candidates for catalyzing cycloadditions leading to hydroquinolines.…”

“…This relative lack led us to consider applying metal-doped zeolites as catalysts for such cycloadditions (Scheme 2), in connection with our recent zeo-click syntheses. [25][26][27][28] We indeed recently demonstrated that Cu I zeolites are very effective and reusable catalysts for the cycloaddition of alkynes with azides or azomethine imines (Scheme 3a and b). [25,26] Therefore, other cycloadditions, such as the reaction of N-arylimines with alkenes should be amenable under similar conditions.…”

Rational Design of Microporous and Mesoporous Solids for Catalysis: From the Molecule to the Reactor

“…In the later case, both the metallic cation and the zeolite acidity intervene in the reaction. [9][10][11] With such a wide range of applications, it is of prime interest to synthesize or post-modify zeolites with a specific tailoring towards a required purpose, and thus to design and produce a well-defined material possessing suitable catalytic properties (proper selectivity and high activity) at the molecular level.…”