Parallel and Combinatorial Chemistry Approaches

This simple sketch illustrates clearly that convergent multicomponent reactions performed with a limited set of reactive building blocks (reactophores) in a multigeneration format offer a tremendous potential to produce diverse small-molecule compound collections, depending on the reaction sequence used (the combinatorics of reactive building blocks ). The concept of combinatorics of reactive building blocks should ultimately lead to novel multicomponent reactions. In Section III we will focus on reactophores such as a-alkynyl ketones, which allow the construction of a wide variety of core structures. 

Novel resin-cleavage strategies have emerged recently as valuable tools in combinatorial and parallel chemistry. The most promising strategies can be summarized as follows  

Cleavage of one specific functional group, such as a carboxylic ester, hydroxamate or amide. This strategy is especially useful to produce focused or targeted libraries. 

Multidirectional cleavage strategies,93,97 98 which offer the possibility to liberate several different functional groups or elements of diversity. Safety-catch linker strategies97,99,100 have been of special interest in this context. 

Cleavage procedures that take advantage of concomitant cyclizations have also proven to be interesting methods to generate novel core structures.12 

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