Crystallization-Induced Dynamic Resolution of Stereolabile Biaryl Derivatives Involving Supramolecular Interactions
datasetposted on 06.06.2012, 00:00 by H. Degenbeck, A.-S. Felten, J. Etxebarria, E. C. Escudero-Adán, J. Benet-Buchholz, A. Vidal-Ferran
Dynamic atroposelective resolutions in mixed Cu(II) complexes derived from stereolabile biphenyl-2,2′-diol and enantiopure 1,2-diamines have been achieved by crystallization. In these cases, all 2,2′-disubstituted biphenyl fragments in the crystal have the same configuration at the stereogenic axis as a result of the transmission of chirality at the molecular level from the chiral inducer (enantiopure diamine ligand) to the dynamically racemic biaryl units by means of supramolecular forces (metal–ligand and hydrogen bonding interactions). Stereoselective synthetic strategies toward [Cu(2,2′-biphenolate)(1,2-diamine)] complexes have been developed, and these derivatives have been characterized and studied by X-ray diffraction. The formation of hydrogen bonds in an intramolecular (between the biphenyl-2,2′-diol and diamine moieties) and in an intermolecular (between the moieties of the copper complex and cocrystallized methanol) way appears to be essential for the induction of chirality.