A facile preparation of 2- and 5-substituted 3-bromothiophenes

Abstract

Acetylenic ketones of type 4 and acetylenic acetals of type 6 ( Scheme 1) are excellent cyclization precursors for the acid-catalyzed synthesis of various heterocycles. Using this methodology, 5- and 2-substituted 3-bromothiophenes of types 7 and 8 have been prepared in good to excellent yields.