PROBLEM TO BE SOLVED: To provide an industrial production method of a synthetic intermediate of anti-hepatitis B virus drug Entecavir.SOLUTION: An industrial production method of an Entecavir synthetic intermediate comprises: opening the ring of a cyclic hemiacetal represented by the formula 2 in the figure under catalysis of a Cu (II) salt by using lead tetraacetate, so as to directly obtain a cyclopentyl formate ester intermediate 3； and performing alcoholysis or hydrolysis of the intermediate 3 in the presence of a base such as potassium carbonate in methanol, so as to obtain a corresponding cyclopentanol compound.SELECTED DRAWING: NoneCOPYRIGHT: (C)2018,JPO&INPIT【課題】抗Ｂ型肝炎ウイルス薬のエンテカビルの合成中間体の工業的な製造方法の提供。【解決手段】下式２で示される環状ヘミアセタールをＣｕ(II)塩の触媒下に四酢酸鉛を用いて開環して、ギ酸シクロペンタチルエステル中間体３を直接的に得、次いで該中間体３をメタノール中、炭酸カリウム等の塩基の存在下にアルコリシス又は加水分解して、対応するシクロペンタノール化合物を得る、エンテカビル合成中間体の工業的な製造方法。【選択図】なし
