3,4-Dibromothiophene, a useful synthetic intermediate, can be prepared by treating tetrabromothiophene with zinc in acetic acid (compare[ 11). Although this synthesis is easily performable, it suffers from the draw-back that the introduction of the fourth bromine atom into the thiophene molecule is a time-consuming operation. Reinecke [2] reported the formation of 3,4-dibromothiophene in cu. 70% yield by treating 2,3-dibromothiophene with four equivalents of sodamide in ...
