title: Regioselective halogenation of thiacalix[4]arenes in the cone and 1,3-alternate conformations.
abstract: Monohalogenation of thiacalix[4]arene in the cone conformation gave either the meta- or para-substituted isomers depending on the halogen and reaction conditions used. Surprisingly, the same reaction with the 1,3-alternate conformer led only to the meta isomer. This is the first example of such a conformation-dependent regioselectivity in calixarene/thiacalixarene chemistry. As the halogen-substituted calixarenes are useful synthetic intermediates, this provided the unique opportunity to functionalize the basic skeleton at two different positions.
authors.affiliation: Department of Organic Chemistry, ‡Laboratory of NMR Spectroscopy, and §Department of Solid State Chemistry, Institute of Chemical Technology, Prague (ICTP) , Technicka 6, 166 28 Prague 6, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Lukášek
authors.forename: Stanislav
authors.initials: S
authors.lastname: Böhm
authors.forename: Hana
authors.initials: H
authors.lastname: Dvořáková
authors.forename: Václav
authors.initials: V
authors.lastname: Eigner
authors.forename: Pavel
authors.initials: P
authors.lastname: Lhoták