Diastereoselective synthesis of a cyclic diamide-bridged biphenyl as chiral atropos ligand

Auras, Stefanie and Trapp, Oliver (2022): Diastereoselective synthesis of a cyclic diamide-bridged biphenyl as chiral atropos ligand. In: Chirality, Vol. 34, No. 5: pp. 813-819

Abstract

Chiral compounds with a 1,2-diamine structure motif and their derivatives are of great interest in organic chemistry and are broadly used in asymmetric transformations, as chiral auxiliaries, (co)ligands, and ligand core structure. Here, we present a straightforward, diastereoselective synthesis for a diamide-bridged biaryl ligand. The ring closing reaction of the racemic atropos biphenyl 6,6'-dimethoxy-[1,1'-biphenyl]-2,2'-dicarboxylic acid with (R,R)-diaminocyclohexane yields the diasteromerically and enantiomerically pure cyclic (S-ax,R,R)-BIPOL, which can be used as a versatile chiral ligand. By NMR spectroscopy, we observed the formation of intermolecular aggregates of the diamide-bridged BIPOL with anhydrous DMSO-d(6). DFT calculations at the B3LYP/6-31G* level of theory corroborate the high interconversion barrier for the biaryl axis of Delta G(not equal) = 148.7 kJ mol(-1) and the favoured formation of (S-ax,R,R)-BIPOL as single stereoisomer.

• Item Type: Journal article
• Faculties: Chemistry and Pharmacy > Department of Chemistry
• Subjects: 500 Science > 540 Chemistry
• ISSN: 0899-0042
• Language: English
• DFG: Gefördert durch die Deutsche Forschungsgemeinschaft (DFG) - 491502892