Synthesis of 2-Substituted 3,5-Dibromothiophenes via a Rearrangement Reaction: A New Example of a Base-Catalyzed Halogen Dance Reaction

Abstract

The reaction of 2,3-dibromothiophene with 1 equivalent of lithium diisopropylamide at -80°C, followed by addition of an electrophile (methyl iodide, methanol, allyl bromide, dimethylformamide, cyclohexanone) gives 2-substituted 3,5-dibromothiophenes selectively and in high yields. The substitution pattern of all products was confirmed by unambiguous assignment of all C-atoms via ¹³C-NMR spectrometry.