Implementation of Stereochemistry in Automatic Kinetic Model Generation

The kinetic model generation code Genesys is extended by the addition of algorithms for the detection of stereocenters and for the detection of stereoisomers. To make this possible, a so-called 2.5D representation of molecules that accounts for the presence of stereocenters and that keeps track of the associated stereoconfiguration of the stereocenters is introduced. A novel algorithm for the detection of steric relations between substituents allows the automated assignment of rate coefficients to stereoselective reactions. The functionality of the algorithms is illustrated for the thermal rearrangement of the monoterpenoid 2-pinanol, an intermediate in the fragrance industry. Accounting for stereochemistry proves to be essential in explaining the reactive behavior of 2-pinanol and the selectivity to its products. Good agreement with experimental data from the literature was obtained. CBS-QB3 calculations for (R)-cis- and (R)-trans-2-pinanol support the experimentally observed differences for the suggested stereoselective and stereospecific reactions.