Combining organocatalysis with transitionmetal catalysis

The use of transition metals or small organic molecules established as catalysts powerful technique in organic synthesis. In recent years combining transition metal with organocatalysis (dual catalysis) has gained considerable attention. The advantage of the dual catalysis is the ability to access pharmaceutically relevant frameworks or building blocks, which is not possible by single catalytic systems. To explore this dual catalytic strategy we initiated a program to use tether technology to combine the transition metal catalysis and organocatalysis for library development. Chapter I deals with combining the organocatalysis with Hg(II) salts for direct alkylation of aldehydes with unactivated alkenes. In chapter II focus is on using a disiloxane linker to combine gold catalysis with enamine catalysis. In chapter III deals with the synthesis of dihydropyridines, which are found in many natural products and biologically active molecules. We attempted to develop titanium promoted reductive coupling of pi-unsaturated substrates with pyridinium salts to access highly substituted dihydropyridines.