Method for preparing canagliflozin intermediate 2-(2-methyl-5-bromobenzyl)-5-(4-fluorophenyl)thiophene

Provide in the present invention is a method for preparing canagliflozin intermediate 2-(2-methyl-5-bromobenzyl)-5-(4-fluorophenyl)thiophene. The method comprises a compound, shown as formula (II), of (5-bromo-2-methylphenyl)[5-(p-fluorophenyl)thiophene-2-yl]ketone being reduced under the action of a directly used borane solution or borane locally produced by reacting alkali metal borohydride with a Lewis acid in a suitable solvent and at a suitable temperature, so as to obtain the compound of formula (I) of 2-(2-methyl-5-bromobenzyl)-5-(4-fluorophenyl)thiophene. The preparation method avoids the use of expensive reductive agents and guarantees the complete conversion of raw materials, wherein the post-treatment is simple, the purity of product obtained is high, the reaction yield is high, in the preparation method is simple and convenient, and can easily be used in industry.