C 2 -Symmetrical 3,4-Ethylenedioxythiophene Monomers through a Divergent Approach.

We present a divergent synthetic approach to C 2 -symmetrical 3,4-Ethylenedioxythiophene (EDOT) monomers in which functionalities can be introduced as pendant chains from the ethylene bridge. The key synthon, obtained through a high yielding trans -etherification, is the chiral EDOT with bromomethyl pendant groups and is prone to substitution reactions with oxygen-based nucleophiles. Elimination of the key precursor affords a diene that can be elaborated into unprecedented PhEDOT monomers using the Diels-Alder reaction. The strategy is further validated by the synthesis of a dithiane-containing EDOT.