Phenylalanine‐Derived Imidazolines Bearing Heteroaromatic Pendants: Synthesis,Characterization, and Application in the Asymmetric Henry Reaction |
| |
| Authors: | Jiří Tydlitát Filip Bureš Zdeňka Růžičková |
| |
| Affiliation: | 1. Institute of Organic Chemistry and Technology, Faculty of Chemical Technology, University of Pardubice, Studentská 573, CZ‐532?10 Pardubice, (phone: +420466037099;2. fax: +420466037068);3. Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, CZ‐532?10 Pardubice |
| |
| Abstract: | Starting from L ‐phenylalanine, (2S)‐3‐phenylpropane‐1,2‐diamine has been prepared and used as building block for the construction of the imidazoline ring. Four new optically pure NH‐imidazolines bearing different six‐membered heteroaromatic substituents on the C(2) position have been prepared and subsequently N‐modified. N‐Substitution afforded two regioisomers that were separated. Some of them proved to be instable and hydrolyzed to diamides. The molecular structures of NH‐imidazolines, both N‐substituted regioisomers, as well as diamides, were unambiguously confirmed by X‐ray‐analysis and NMR spectra. The successfully prepared imidazolines, as well as diamides, were applied as catalysts in a Cu(II)‐catalyzed Henry reaction achieving 26–98% chemical yields and enantiomeric excesses of 3–42%. |
| |
| Keywords: | Imidazolines L‐Phenylalanine Henry reaction Enantioselective catalysis |
|
|
