Although the Michael addition is a very well-known and widely applied reaction, cost-effective, metal-free, and readily prepared organic catalysts remain rare. A chiral, bifunctional, (R,R)-1,2-diphenylethylenediamine-derived thiourea organic catalyst was developed and applied to asymmetric Michael additions of nitroalkenes under neutral conditions. Generally, fluorine-substituted thiourea catalysts exhibited high chemical yields and enantioselectivities under neutral conditions. The mild reactions were tolerant of many functional groups and afforded good-to-excellent yields, as well as high diastereo- and enantioselectivities for the Michael adducts. The utility of the transformation was demonstrated by the synthesis of a bioactive compound, (R)-Phenibut.
Bibliographical noteFunding Information:
We are grateful for nancial support by Dr K. H. Kim. We gratefully acknowledge the support from National Research Foundation of Korea (NRF-2019R1814112), (NRF-2020R1C1C1-013785). We thank Dr Yeonsun Hong for providing assistance.
© The Royal Society of Chemistry 2020.
ASJC Scopus subject areas
- Chemical Engineering(all)