Design and synthesis of imidazolinium salts derived from (l)-valine. Investigation of their potential in chiral molecular recognition

Abstract

Several imidazolinium salts are synthesized from (L)-valine. A study of the structure relationships is achieved to obtain high diastereomeric interactions with an anionic substrate. High splitting up to 60 Hz of the (rac)-potassium Mosher's salt are observed by NMR spectroscopy.

Design of Chiral Hydroxyalkyl‐ and Hydroxyarylazolinium Salts as New Chelating Diaminocarbene Ligand Precursors Devoted to Asymmetric Copper‐Catalyzed Conjugate Addition

“…[15] In the first approach, the mixed-anhydride-mediated coupling between commercially available Boc-protected amino acids 10 and substituted anilines led to the formation of the corresponding amides. After the removal of the carbamate by anhydrous hydrochloric acid in methanolic solution, the amide function was reduced with LiAlH 4 to afford, after chromatography, the diamines 11 in excellent yields.…”

Metathesis of 1‐Octene in Ionic Liquids and Other Solvents: Effects of Substrate Solubility, Solvent Polarity and Impurities

“…[6] Grubbs 1 st and 2 nd generation, and ruthenium allenylidene catalyst precursors have been investigated in detail in ring-closing metathesis. [7][8][9][10][11][12][13][14][15][16][17] Many of these reactions feature high selectivities and high reaction rates in the first run, which then decrease upon recycling due to catalyst leaching or deactivation. However, attachment of an "ionic liquid tag" to catalyst ligands hugely improves the recyclability of the system.…”

Applications of Chiral Ionic Liquids

“…[56] Once again, the presence of a phenyl group, in this case with an additional bulky tert-butyl substituent in ortho position was crucial for strong interactions. Additionally, a hydroxyethyl substituent was introduced for hydrogen bonding towards the cation.…”