title: Stereochemical Communication within a Chiral Ion Pair Catalyst.
abstract: Ionic interactions are increasingly appreciated as a key, asymmetry-inducing factor in enantioselective catalytic transformations, including those involving Brønsted acid or base catalysis, phase-transfer catalysis, and related processes. However, a detailed understanding of these interactions is often lacking. Herein, we show how an enantiopure anion enforces a chiral conformation onto a catalytically relevant achiral cation. Specifically, we use vibrational circular dichroism (VCD) spectroscopy to monitor the transmission of stereochemical information from a chiral phosphate anion to a flexible manganese(III)-salen cation. We show that VCD can be used to study solvent effects and that the obtained chiroptical data directly and quantitatively correlate with the experimentally observed enantioselectivity in an asymmetric olefin epoxidation reaction.
authors.affiliation: Fakultät für Chemie und Biochemie, Ruhr-Universität Bochum, Universitätsstrasse 150, 44801 Bochum (Germany). christian.merten@ruhr-uni-bochum.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Merten
authors.affiliation: Fakultät für Chemie und Biochemie, Ruhr-Universität Bochum, Universitätsstrasse 150, 44801 Bochum (Germany).
authors.forename: Corina H
authors.initials: CH
authors.lastname: Pollok
authors.affiliation: Max-Planck Institut für Kohlenforschung, Kaiser Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany).
authors.forename: Saihu
authors.initials: S
authors.lastname: Liao
authors.affiliation: Max-Planck Institut für Kohlenforschung, Kaiser Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany). list@kofo.mpg.de.
authors.forename: Benjamin
authors.initials: B
authors.lastname: List
keywords: asymmetric catalysis; asymmetric counterion-directed catalysis (ACDC); chirality transfer; ionic interactions; vibrational circular dichroism