Stereoselective organocatalysis and flow chemistry

Abstract

Organic synthesis has traditionally been performed in batch. Continuous-flow chemistry was recently rediscovered as an enabling technology to be applied to the synthesis of organic molecules. Organocatalysis is a well-established methodology, especially for the preparation of enantioenriched compounds. In this chapter we discuss the use of chiral organocatalysts in continuous flow. After the classification of the different types of catalytic reactors, in Section 2, each class will be discussed with the most recent and significant examples reported in the literature. In Section 3 we discuss homogeneous stereoselective reactions in flow, with a look at the stereoselective organophotoredox transformations in flow. This research topic is emerging as one of the most powerful method to prepare enantioenriched products with structures that would otherwise be challenging to make. Section 4 describes the use of supported organocatalysts in flow chemistry. Part of the discussion will be devoted to the choice of the support. Examples of packed-bed, monolithic and inner-wall functionalized reactors will be introduced and discussed. We hope to give an overview of the potentialities of the combination of (supported) chiral organocatalysts and flow chemistry.

Advanced In-Line Purification Technologies in Multistep Continuous Flow Pharmaceutical Synthesis

“…Early efforts devoted to the development of immobilized catalysts in flow chemistry involved polystyrene resin-bound piperidine for catalytic Knoevenagel reaction and toluenesulfonic acid for catalytic benzaldehyde acetal formation . To date, a wide variety of immobilized catalysts have been employed in flow chemistry, including chiral catalysts for enantioselective transformations. − …”