The invention relates to a preparation method of an
omarigliptin intermediate. The
omarigliptin intermediate is tert-butyl [1-(2,5-difluorophenyl)-1-oxopent-4-yn-2-yl]
carbamate. The method comprises the following steps: a compound I shown as the formula (III) is prepared from 1,4-difluorobenzene as a starting material; the compound I is subjected to a reaction with dibenzimide, and a compound II shown as the formula (IV) is obtained; the compound II is subjected to a
substitution reaction with a
propargyl compound, and a compound III shown as the formula (V) is prepared; the compound III is subjected to acidolysis and Boc protection, and the compound, namely, the
omarigliptin intermediate, shown as the formula (II) is obtained. According to the preparation method, technical defects of long synthesis steps, quite expensive starting materials such as 2,5-difluorobenzaldehyde or 2-bromo-1,4-difluorobenzene, preparation of Weinreb amides, use of CDI (1,1'-
Carbonyldiimidazole) and the like in the prior art are overcome; the preparation method has the advantages of simple operation, high yield, low cost and wide source of raw materials and the like, and is applicable to industrial production.