This work reviews the authors’ choice of recently published papers where at least one asymmetric quaternary stereocenter has been formed via organocatalysis. The scope and limitations of the reactions are highlighted. 1 Introduction 2 Alkylation and Arylation Reactions 3 Addition to Carbon-Carbon Multiple Bonds 4 Addition to N=X Double Bonds 5 Nucleophilic Aziridine-Ring Opening 6 Aldol and Related Reactions 7 Brønsted Acid Organocatalyzed Formation of Nitrogen-Containing Quaternary Stereocenters 8 Halogenation and Pseudohalogenation Reactions 9 Epoxidation 10 Diels-Alder Reaction 11 N-Heterocyclic Carbene Catalysis 12 Cascade Reactions 13 Conclusion and Outlook

This review provides the authors’ selection of recent publications that highlight the increasing efforts to develop valuable organocatalytic domino/tandem/cascade reactions as the main tool in the creation of quaternary stereocenters. 1 Introduction 2 Diarylprolinol Ethers and Proline Derivatives 3 Imidazolidinones 4 Brønsted Acids 5 Cinchona Alkaloids 6 Thioureas 7 Squaramides 8 N-Heterocyclic Carbenes 9 Outlook and Conclusions

PEP and aldolase mimicry is the key for a direct organocatalytic entry to precursors of ulosonic acids, biomolecules of enormous importance in biology, chemistry and medicine; in the key aldol reaction the dimethylacetal of pyruvic aldehyde is used as phosphoenolpyruvate (PEP) equivalent and the amino acid proline functions as an organocatalyst, imitating the enzyme.