Unprecedented Chiral Functionalized Biochar for Asymmetric PTC

Abstract

A chiral biochar/onium salt synthesis by mechanochemical functionalization of biochar and quinine hydrochloride is here reported, providing the adduct in good mass yield, in solvent-free conditions, and in short reaction time. This sustainable functionalization results in an unprecedented chiral phase transfer catalyst biochar-based for the preparation of asymmetric alkylation products of glycine derivatives. The reaction is promoted by 5 mol% catalysts providing high efficiency and moderate enantioselectivity. The product can be easily recovered by ethyl acetate extraction as well as the catalyst in water solution. Being heterogeneous, the catalyst can be easily recovered and mechanochemically regenerated without reduction of efficiency and enantioselectivity.