The LILITH approach to organic synthesis planning

The general basis of the LILITH program is outlined. The size of the possible solution space is reduced by enhancing convergence, simplification and ordering. Complexity distance, relevant bond sets and ordering for bond-forming sequences are described. The evaluation of reactivity is the second main aspect in organic synthesis planning. Properties involving the ground state (native bond polarity) and the excited state (group-similar interference) contribute to the prediction of reactivity.