Streamlining Organic Free Radical Synthesis through Modern Molecular Technology: from Polymer Supported Synthesis to Microreactors and Beyond

Increasing emphasis has been placed on producing synthetic organic compounds faster and more efficiently than can be produced using conventional methodology. It is often observed that tried and true methods for performing synthesis, work-up, and purification on individual or low number of reactions do not scale up well even to a modest level of parallel synthesis. As a result, novel methodologies or parallel and combinatorial chemical synthesis continues be developed at a rapid pace. In general, the specific structure of the target molecule(s) guides the selection of the synthetic methodology (e.g., solid or solution phase) used in given reaction sequence. The phrase “Streamline Organic Synthesis” has been coined as descriptor for methodology that lends itself to efficient application to parallel organic synthesis. The advantages of the past few years in microreactors have demonstrated the miniaturizing of chemistry that significant advantage with respect to cost, safety, throughput, kinetics and scale-up. The use of chemical microreactors for broad spectrum of important chemical transformation has illustrated the utility and benefits for both chemical discovery and development of novel and unique applications. The main objective of this tutorial review article is to bring together two important topics of synthetic free radical chemistry and its applications and advancements to “Streamline Organic Synthesis” on the interface of conventional and alternative materials, such as polymer supported reagents/reactants, use of ultraporous materials (PolyHIPEs) as well as continuous microflow systems of natural zeolite and commercial man-made microreactors.