An easy and effective approach towards heterogeneous Pt/SiO2-cinchonidine catalyst system for enantioselective hydrogenation of ethyl pyruvate

A single unit catalyst system (Pt/silica–chiral modifier) is developed for the enantioselective hydrogenation of ethyl pyruvate. Cinchonidine was tethered directly without prior modification over carboxylate functionalized SBA-15 by the reaction of vinyl group in cinchonidine with –COOH group in functionalized SBA-15 through ester linkage. Then Pt nanoparticles were deposited over cinchonidine tethered SBA-15. The mesostructures were characterized by small-angle XRD, N2 sorption and TEM, while the surface functionalization was confirmed by FTIR, TG/DTA and solid state 13C NMR. Enantioselectivity of the catalyst system for hydrogenation of ethyl pyruvate was determined by GC/FID. The highest enantiomeric excess was achieved as 70.8% and the catalyst recyclability was authenticated even after 3rd reuse without significant loss in enantiomeric excess.

Graphical abstractA single unit heterogeneous Chiral catalyst system (Pt/CA-SBA-CD) is prepared for the enantioselective hydrogenation of ethyl pyruvate. Cinchonidine is tethered successfully with carboxylate functionalized SBA-15 which is further impregnated by Pt nanoparticles. The highest enantiomeric excess was achieved as 70.8% with adequate recyclability.Figure optionsDownload full-size imageDownload high-quality image (106 K)Download as PowerPoint slideResearch highlights▶ A unique heterogeneous chiral catalyst is developed for hydrogenation. ▶ Cinchonidine is directly tethered with CA-SBA-15. ▶ Pt nanoparticles deposit in the channels of cinchonidine-tethered CA-SBA-15. ▶ Catalyst system provides a maximum of 70.8% e.e. value with adequate recyclability.