Michael addition is an important reaction because it can be used to synthesize a wide range of natural products or complex compounds that exhibit biological activities. In this study, a mirror image of an aldehyde and α,β-unsaturated nitroalkene were reacted in the presence of (R,R)-1,2-diphenylethylenediamine (DPEN). Herein, thiourea was introduced as an organic catalyst, and a selective Michael addition reaction was carried out. The primary amine moiety of DPEN reacts with aldehydes to form enamines, which is activated by the hydrogen bond formation between the nitro groups of α,β-unsaturated nitroalkenes and thiourea. Our aim was to obtain an asymmetric Michael product by adding 1,4-enamine to an alkene to form a new carbon–carbon bond. As a result, the primary amine of the chiral diamine was converted to an enamine. The reaction proceeded with a relatively high degree of enantioselectivity, which was achieved using double activation via hydrogen bonding of the nitro group and thiourea. Michael products with a high degree of enantioselectivity (97–99% synee) and diastereoselectivity (syn/anti = 9/1) were obtained in yields ranging from 94–99% depending on the aldehydes.
Bibliographical noteFunding Information:
Funding: This study was supported by the National Research Foundation (NRF) and funded by the Korean government (MSIT) (2021R1A6A3A01087948). This research was supported by the Bio & Medical Technology Development Program of the National Research Foundation (NRF) and funded by the Korean government (MSIT) (2021M3A9G1097744). In addition, this study was supported by a Korea University grant.
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.
- Asymmetric synthesis
- Michael addition
- Thiourea catalyst
ASJC Scopus subject areas
- Environmental Science(all)
- Physical and Theoretical Chemistry