Centre for Molecular and Biomolecular Informatics Radboud University Nijmegen

Chemical reactions can be viewed in two directions: the synthetic direction, corresponding to laboratory operations, and the retrosynthetic (or antithetic) direction, going backwards from a target molecule to starting materials by way of retro-reactions or transforms. Retrosynthesis is often applied when a synthetic route to a target molecule has to be developed. The term retrosynthetic analysis, a synonym for retrosynthesis, expresses more clearly its `imaginary' character.

The most important computer programs for synthesis design (a prime example is LHASA) operate in a retrosynthetic fashion. The reason for this is that retrosynthetic analysis lends itself well to a description in algorithms and thence in computer programs.

The following chapters provide an overview of retrosynthetic analysis:

• Analysis of Complex Synthetic Problems
• Terminology
• Retrosynthetic Strategies
• Goals and Subgoals
• Computer-Assisted Retrosynthetic Analysis