STEREOSELECTIVE CATALYTIC REACTIONS UNDER CONTINUOUS FLOW CONDITIONS

This PhD Thesis deals with the application of different catalytic methodologies under continuous flow conditions. In particular, the combination of flow chemistry with different enabling technologies is explored. In Chapter 1 the combination of continuous flow processes with the use of different solid supported chiral organocatalysts is described. The fabrication of chiral, packed-bed and monolithic, organocatalytic reactors and their use in stereoselective transformations are reported. The possibility to recycle the immobilized chiral catalysts is also discussed. - In section 1.2 the use of polystyrene- and silica-supported chiral imidazolidinones to perform continuous flow stereoselective Diels-Alder cycloadditions and stereoselective aldehydes alkylation is studied. - In section 1.3 the immobilization onto different materials of primary amines derived from Cinchona alkaloids and the application under flow conditions are explored. - In section 1.4 chiral picolinamides for the continuous stereoselective reduction of imines with trichlorosilane are studied. Chapter 2 describes the application of different synthetic strategies using flow micro(meso)-reactors, aimed to the synthesis of chiral active pharmaceutical ingredients or immediate advanced precursors of compounds of industrial interest. In particular, - in section 2.2 the organocatalytic, stereoselective synthesis of (S)-Pregabalin and (S)-Warfarin within microreactors is investigated. - Section 2.3 presents the continuous flow synthesis of primary amines through a metal-free reduction of nitro compounds with trichlorosilane. - In section 2.4 a catalytic strategy for a multistep synthesis of chiral, biological active 1,2-amino alcohols using 3D-printed flow reactors is highlighted. Chapter 3 covers the research work carried out during my research period in Aachen, Germany which was focused on the development of a new synthetic methodology using photoredox catalysis. In particular, the photocatalytic reductive coupling of imine with olefins for the preparation of -amino esters and its application under continuous flow conditions are discussed.