Catalysts based on (R, R)-1,2-diphenylethylenediamine are, as chiral organic catalysts, applied to the asymmetric Michael addition to α, β-unsaturated nitroalkenes under neutral conditions. The role of an aqueous medium for organic catalytic activity can be reversed concerning hydrophilic-hydrophobic function depending on the reaction conditions. In this study, to provide an environmentally friendly system, the thiourea-based catalyst substituted with 3,5-(CF3 )2-Ph was used in water solvents. The hydrophobic effect of the substituent provided fast reaction, high chemical yield, and mirror-image selectivity. This reaction allowed the preparation of GABAB agonists in an optically pure manner. Additionally, GABA (γ-aminobutyric acid) analogs such as baclofen and phenibut were synthesized as R-type S-type with high optical purity.
Bibliographical noteFunding Information:
Funding: This study was supported by the National Research Foundation of Korea (NRF-2021M3A9-G1097744), (NRF-2021R1A6A3A01087948). Also, this study was supported by a Korea University Grant.
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
- Calcium release
- Inhibitor of GABA receptor
- Michael addition
- Organic chemistry
ASJC Scopus subject areas
- Environmental Science(all)
- Physical and Theoretical Chemistry