Over the past decade several peptides have emerged as efficient organocatalysts for various asymmetric transformations.1 Within our project dedicated to the development of organocatalysts based on amino acids and peptides, we have reported that primary amine-thioureas based on di-tert-butyl aspartate are excellent organocatalysts for the Michael reactions.2 Herein, we present our work based on simple amino acids and peptides that can be efficiently employed as catalysts for the aldol reaction, the Michael reaction and the epoxidation reaction. Tripeptide and tripeptide mimetics based on proline have been employed for the aldol reaction leading to high yields (up to 99%) and selectivities (up to 99% ee).3 More recently, we have disclosed the use of either phenylalanine or aspartate derivatives as catalysts for the Michael reaction between aldehydes and maleimides leading to substituted succinimides in high yields and selectivities with low catalysts loading (1 mol%).4 Aspartate derivatives were also found to catalyze efficiently the asymmetric α-amination of α,α-disubstituted aldehydes leading to products that can be transformed to enantioenriched α,α-disubsituted amino acid derivatives.5 Finally, our efforts have been focused on the design and synthesis of tripeptides bearing thioureas that can be employed as catalysts for the asymmetric epoxidation reaction of olefins.
Acknowledgment. The author gratefully acknowledge the Operational Program “Education and Lifelong Learning” for financial support through the NSRF program “ΕΝΙΣΧΥΣΗ ΜΕΤΑΔΙΔΑΚΤΟΡΩΝ ΕΡΕΥΝΗΤΩΝ” (PE 2431)” co-financed by ESF and the Greek State