The structural proliferation of fluorinated building blocks by regiochemically exhaustive functionalizations

Organofluorine compds. do not grow on trees. They have to be prepd. by introducing the halogen into the carbon backbone at a suitable stage of the synthesis sequence. From a logistic point of view, the key question is, when exactly. For example, if one deals with a well defined target structure, fluorine will often be delivered at a late stage as a precaution to avoid undesired consecutive transformations. A totally different scenario is encountered if the work aims at creating mol. diversity in the hope to find "leads" for further development. Under such circumstances one will start from a readily available core compd. which already contains the fluorine label. When elaborating this starting material into all possible directions, the methods employed must be capable of attaching any functional group at any vacant position of the core compd. This double condition of product flexibility and regioisomeric exhaustiveness is most readily met by modern organometallic techniques, as will be demonstrated. [on SciFinder (R)]