Preparation method of chiral intermediate of omarigliptin

The invention discloses a novel synthesis method for preparing a chiral intermediate of omarigliptin. The method comprises the following steps: carrying out amidation, alder condensation, hydrazine hydrate condensation, rearrangement, Boc addition, ring opening and Grubbs catalyst ring formation on starting raw materials including crotonyl chloride and (S)-4-benzyl-2-oxazolidone and carrying out hydrolysis to obtain the chiral intermediate (IX). The preparation method disclosed by the invention has the advantages of relatively low cost, easiness for obtaining raw materials and relatively high yield, so that the preparation method is suitable for industrial production. The formula (IX) is shown in the description. 本发明公开了种新的制备奥格列汀的手性中间体的合成方法，该方法包括以起始原料巴豆酰氯和(S)-4-苄基-2-唑烷酮经酰胺化，alder缩合，水合肼缩合，重排，上Boc，开环，Grubbs催化剂成环并水解得到手性中间体(IX)。本发明的制备方法成本较低，原料易得，产率较高，适于工业化生产。