The topic of this doctoral thesis is the non-covalent organocatalysis with thiourea derivatives. After a review of the worldwide achieved best results in the field of asymmetric organocatalysis with thiourea derivatives our already published results on the mode of action of the bis(trifluoromethyl)phenyl group in thiourea organocatalysts are shown. The also already published studies on the conformation of an Evans auxiliary with tin(IV) tetrachloride follow. The further chapters present our efforts to highlight the mechanism of the organocatalytic alcoholysis of styrene oxides, a non-catalyzed Passerini reaction as well as the synthesis of 1,4-dioxepins catalyzed by a thiourea derivative. In the last chapters we show our attempts toward the realization of an organocatalytic Sharpless dihydroxylation , towards the synthesis of oxazolidinones catalyzed by thiourea derivatives and towards the development of an organocatalytic Prins reaction.
