Convenient method for the preparation of the 2-methyl thiophen-3-yl magnesium bromide lithium chloride complex and its application to the synthesis of 3-substituted 2-methylthiophenes

摘要

Lithium chloride was found to accelerate formation of the Grignard reagent from inactive 3-bromo-2-methylthiophene (1) and commercial magnesium metal. Based on this finding, a convenient and potentially scalable preparation of ethyl 2-methylthiophene-3-carboxylate (3) was achieved. In addition, this process has been found to provide a new, general approach to 3-substituted 2-methylthiophenes.