Reactions of diarylvinylidenecyclopropanes with bromine at −100 °C in dichloromethane and ether. A drastic solvent effect

The reaction of diarylvinylidenecyclopropanes with bromine produces the corresponding brominated indene derivatives and conjugated triene derivatives in good to high yields in dichloromethane and ether, respectively, at −100 °C within 10 min.