Computer-oriented representation of stereoselective synthetic methods

Computer programs which are designed to assist in the planning of organic syntheses can suggest pertinent solutions only if they use an adequate computer-oriented representation of synthetic methods. In order to generate synthetic precursors from a given target, these programs use retrosynthetic representations of synthetic methods, so-called transforms. Although stereochemistry is an essential factor of synthetic complexity, up to now only few efforts have been made to represent the stereochemical aspect of transforms. The known approaches exclusively rely on basic knowledge about the stereochemical course of reactions, and every transform is described in terms of a few elementary stereochemical operations. Although this works satisfactorily in numerous cases, there remain nevertheless valuable stereoselective synthetic methods the description of which requires taking into account a more complex stereochemical knowledge. In order to solve this problem, we propose a general computer-oriented representation of the stereochemical aspect of transforms.