Organic synthesis planning: An algorithm for selecting strategic bond forming sequences

An algorithm part of a computer program (Lilith) or convergent retrosynthesis planning is described. It chooses the optimal forming sequence tor a given set of strategic bonds. Its heuristic rules consider complexity distances, steric congestions and ease of cyclization. The procedure used for fast evaluation of approximated congestion at reaction center is outlined. Linkings of the alqorithm with the previous parts and with the general approach of Lilith are emphasized. Applications to natural substance synthesis projects are exemplified.