title: Pseudotetrahedral polyhaloadamantanes as chirality probes: synthesis, separation, and absolute configuration.
abstract: Pseudotetrahedral, conformationally as well as configurationally stable 1-bromo-3-chloro-5-fluoro- (4) and 1-bromo-3-chloro-5-fluoro-7-iodoadamantane (5) (and some related compounds) were prepared by our recently devised phase-transfer catalytic halogenation protocol; the optical antipodes of 4 were separated by HPLC on chiral phase in ee > 99%, and the absolute configurations were assigned by matching observed and computed circular dichroism spectra. Structure 5 is the first chiral aliphatic hydrocarbon containing all stable (nonradioactive) halogens; its structure was proven by NMR spectroscopy and by X-ray crystal data. We emphasize that the combination of experiment and theory is very powerful in assigning absolute configurations even for molecules without typical chromophors, with small values for the optical rotation, and without an atom at the stereogenic center.
authors.affiliation: Institut für Organische Chemie der Justus-Liebig-Universität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany. prs@chem.uga.edu
authors.forename: Peter R
authors.initials: PR
authors.lastname: Schreiner
authors.forename: Andrey A
authors.initials: AA
authors.lastname: Fokin
authors.forename: Oliver
authors.initials: O
authors.lastname: Lauenstein
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Okamoto
authors.forename: Tsuneki
authors.initials: T
authors.lastname: Wakita
authors.forename: Christopher
authors.initials: C
authors.lastname: Rinderspacher
authors.forename: Gregory H
authors.initials: GH
authors.lastname: Robinson
authors.forename: Jason K
authors.initials: JK
authors.lastname: Vohs
authors.forename: Charles F
authors.initials: CF
authors.lastname: Campana