Silver-Exchanged Zeolite Y Catalyzes a Selective Insertion of Carbenes into C–H and O–H Bonds

Abstract

Commercially available zeolite Y modulates the catalytic activity and selectivity of ultrasmall silver species during the Buchner reaction and the carbene addition to methylene and hydroxyl bonds, by simply exchanging the counter cations of the zeolite framework. The zeolite acts as a macroligand to tune the silver catalytic site, enabling the use of this cheap and recyclable solid catalyst for the in situ formation of carbenes from diazoacetate and selective insertion in different C−H (i.e., cyclohexane) and C−O (i.e., water) bonds. The amount of catalyst in the reaction can be as low as ≤0.1 mol % silver. Besides, this reactivity allows deeply drying the HY zeolite framework by making the strongly adsorbed water molecules react with the in situ formed carbenes.

State-of-the-art strategies for the synthesis of zeolite-encapsulated subnanometric metal clusters

“…102 In addition to the photochemical reactions described above, the Ag 8-10 @FAU catalyst, obtained by ion exchange followed by auto-reduction at 450 °C, has been used for the addition reaction of CH 2 COOEt carbene, in situ generated from diazo compounds N 2 CH 2 COOEt, to alcohols and arenes. 103 In this case, the electron density of the clusters can also be fine-tuned by the selection of counter-ion, with the sodium and lithium forms of the zeolite providing the highest activity in both reactions.…”