Preparation method for canagliflozin

The invention relates to a novel synthesis method for 1-(Beta-D-glucopyranosyl)-4-methyl-3-[5-(4-fluorophenyl)-2-thienylmethyl]benzene (canagliflozin). 2-(4-fluorophenyl)-5-[(5-halogeno-2-methylphenyl)methyl]thiophene and 2,3,4,6-tetrakis-O-(trimethylsilyl)-D-glucono-1,5-lactone are dissolved in organic solvent and carry out condensation reaction under the catalysis of a metallic lithium derivative, and thereby intermediate (II) is produced; the intermediate (II) undergoes catalytic hydrogenation reaction, so that intermediate (III) is further produced, and finally, compound (I), namely the canagliflozin is obtained by acidification hydrolysis. Because the preparation method disclosed by the invention replaces a virulent BF3/triethyl silicane reduction system with the environment-friendly catalytic hydrogenation technique, the preparation method is technically safer, environment-friendly, low in cost and more suitable for industrial production.