Halogen-dance (HD) reactions at aromatic systems,
in particular applied to various brominated
thiophenes and furans, lead to rearranged lithiated species after treatment of the
halogenated starting compounds with LDA. They have been studied thoroughly within our group
[1-4], as they open
promising pathways to highly substituted heterocycles. Until now, no efforts have been made
to adopt this approach to 2,2-bithiophene-systems.
In this work we present HD techniques to afford mono- and double-rearranged lithium intermediates
which yield - after treatment with various electrophiles - mono- and double-substituted
dibromo-2,2'-bithiophenes A,B and C.
