Novel synthetic method for entecavir compound

The invention belongs to the field of drug synthesis and relates to an entecavir compound and a synthetic method of an intermediate of the entecavir compound. The novel synthetic method comprises: by taking (S)-3-hydroxyl dimethyl adipate as an initial raw material, preparing an intermediate 9 through hydroxyl TBS protection, Dieckmann condensation reaction, ketone protection to ketal, ester group reduction to hydroxyl, hydroxyl protection, deprotection, ketone to silyl enol ether and Rubottom oxidizing reaction; and preparing entecavir from the intermediate 9 through wittig reaction, Mitsunobu reaction, silicon preventing radical group removal and basic hydrolysis. The novel synthetic method provided by the invention is mild and easily controllable in reaction condition, simple to operate, high in product yield, high in purity and suitable for industrialized mass production.