posted on 2014-10-03, 00:00authored byJan Lukášek, Stanislav Böhm, Hana Dvořáková, Václav Eigner, Pavel Lhoták
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.