Towards a rational design of enantioselective heterogeneous catalysts: Modeling of chiral organotin precursors

In this work, the modeling of organotin compounds of general formula Men-Sn-R-3 (Men = menthyl, R = alkyl or alkoxyalkyl) is carried out. These compounds can be employed as precursors for obtaining enantioselective heterogeneous catalysts, prepared by means of Surface Organometallic Chemistry on Metals techniques. Both Molecular Mechanics and Molecular Dynamics, as well as Density Functional Theory (DFT), were used to give an insight into the relative stability of the Sn-C bonds of several different organotin compounds. The calculations carried out on the molecules Men-Sn-(iso-Bu)(3) and Men-Sn-((1-OCH3)-Et)(3) showed that if these molecules are used as precursor compounds to prepare heterogeneous organobimetallic catalysts, the probability of losing the menthyl group in a dissociation process is lower, leading to a better performance of the resulting catalysts, in terms of enantiomeric excess. (C) 2010 Elsevier B.V. All rights reserved.