title: A Supramolecular Chiral Auxiliary Approach: "Remote Control" of Stereochemistry at a Hierarchically Assembled Dimeric Helicate.
abstract: Dimeric hierarchically-assembled titanium(IV) helicates are in solvent-dependent equilibrium with the corresponding monomers. Statistically formed mixtures of such complexes bearing chiral stereocontrolling ligands and achiral diene-substituted ligands show high diastereoselectivity and reasonable enantioselectivity in the Diels-Alder reaction with maleimides if the reaction proceeds with the dimer but not with the monomer. Thus, solvent dependent switching between the monomer and dimer enables on/off switching of the enantioselectivity.
authors.affiliation: Institut für Organische Chemie, RWTH Aachen, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Van Craen
authors.affiliation: Institut für Organische Chemie, RWTH Aachen, Landoltweg 1, 52074, Aachen, Germany. Markus.Albrecht@oc.rwth-aachen.de.
authors.forename: Markus
authors.identifier: http://orcid.org/0000-0002-3501-1477
authors.initials: M
authors.lastname: Albrecht
authors.affiliation: Institut für Organische Chemie, RWTH Aachen, Landoltweg 1, 52074, Aachen, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Raabe
authors.affiliation: Department of Chemistry, University of Jyväskylä, P.O. Box 35, 40014 University, Jyväskylä, Finland.
authors.forename: Fangfang
authors.initials: F
authors.lastname: Pan
authors.affiliation: Department of Chemistry, University of Jyväskylä, P.O. Box 35, 40014 University, Jyväskylä, Finland.
authors.forename: Kari
authors.initials: K
authors.lastname: Rissanen
keywords: Diels-Alder reaction; helicates; lithium; self-assembly; titanium