Preparation of chiral organic-inorganic solid hybrids. Use as support of catalysts in the enantioselective hydrogenation of ethyl pyruvate

Abstract

Chiral organic-inorganic hybrids have been prepared from 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS), divynilbenzene (DVB) and a natural alkaloid (-)-Cinchonidine (CD). Different CD quantities were inserted into the solid by hydrosilylation reaction using Pt02 as catalyst. The obtained solids were used as supports of Ru which was deposited on the carrier from colloidal dispersion of the metal. Catalysts and supports were characterised by using Fourier Transformed Infrared Spectroscopy, X- Ray Diffraction, Electron Transmission Microscopy, N2 adsorption-desorption isotherms and X- Ray photoelectron spectroscopy. The catalysts were essayed in the hydrogenation of ethyl pyruvate at 298 K and 40 bar of hydrogen in a Parr-type reactor. The obtained results indicate that the catalytic activity of the hybrid catalysts is rather low and in those catalysts having CD in their structure, is possible to induce chirality towards the enantiomer R-lactate. © 2007 Sociedad Chilena de Química.