Sustainable approach for the synthesis of chiral β-aminoketones using an encapsulated chiral Zn(ii)–salen complex

Abstract

To enable sustainable chemical transformations, it is imperative to adopt ecofriendly strategies aligned with economic growth and environmental preservation. We present a more environmentally conscious method for synthesizing Zn(II)–salen ligand encapsulated within an MWW host as a heterogeneous chiral catalyst, denoted as Zn(II)–salen@MWW. Various techniques, including FTIR, FESEM, EDX, XRD, BET, and XPS were used to confirm the successful chiral Zn(II) ligand encapsulation. Utilizing an uncomplicated ultrasonic approach, the synthesized catalyst efficiently produces chiral β-amino carbonyl compounds at room temperature under solvent-free conditions. The catalytic process takes 120 minutes, yielding an impressive 94% with selectivity >94%. This protocol offers multiple benefits, including an environmentally friendly catalyst, simple setup, easy separation, and the capability to reuse the chiral Zn(II)–salen@MWW catalyst for up to five runs. Substrate tests involving aldehydes, ketones, and anilines exhibit yields ranging from 96% to 80% and selectivity from 96% to 83%. The process holds significant potential for academia and industry.