Regioselective Halogenation of Thiacalixarenes in the Cone and 1,3-Alternate Conformations
journal contributionposted on 2014-10-03, 00:00 authored by Jan Lukášek, Stanislav Böhm, Hana Dvořáková, Václav Eigner, Pavel Lhoták
Monohalogenation of thiacalixarene 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.