Chiral pyridine oxazoline and 1,2,4-triazine oxazoline ligands incorporating electron-withdrawing substituents and their application in the Cu-catalyzed enantioselective nitroaldol reaction

Abstract

Eight pyridine-containing and four 1,2,4-triazine-containing chiral oxazoline ligands incorporating electron-withdrawing substituents have been synthesized by two-step route including Buchwald–Hartwig amination. Enantio-inducing activity of the ligands has been assessed in the copper-catalyzed asymmetric nitroaldol reactions and the influence of the electron-withdrawing substituents on the ligands' activity has been investigated. Graphical abstract

Novel Copper(II) Complexes with Dipinodiazafluorene Ligands: Synthesis, Structure, Magnetic and Catalytic Properties

“…Chiral pyridines are of great interest from many points of view [1] and are being actively investigated as ligands in coordination chemistry [2][3][4][5], as chiral auxiliary [6][7][8][9][10][11][12], as biologically active compounds [13,14], including anticancer agents [15], as building blocks in the design of receptors for enantioselective recognition [16], chiral coordination frameworks [17], luminescent materials [18,19], and calamitic liquid crystals [20]. The coupling of a pinane carbon frame and pyridine ring system in one molecule generates an extensive group of pinane-pyridine hybrids (pinopyridines) [21][22][23][24][25][26][27][28][29][30][31][32][33].…”