| 摘要 |
PURPOSE:To efficiently obtain the titled substance useful as a key intermediate for prostaglandins I1, by cyclizing a propargylcylcopentane with a reducing agent using an alkali (earth) metal and, as necessary, deprotecting the reduction product. CONSTITUTION:A compound expressed by formula I (R<11> and R<21> are tri 1-7C hydrocarbonsilyl or a group together with O of the hydroxyl group forming acetal bond; R<3> is H, CH3 or vinyl; R<4> is alkyl, alkenyl, phenyl, etc.; n is 0 or 1) or an enantiomer thereof is cyclized with a reducing agent using an alkali (earth) metal and, as necessary, deprotected to give a compound expressed by formula II. The compound expressed by formula I is used in a molar amount of preferably 1.2-10.0 times based on 1mol compound expressed by formula I and as an anion radical solution containing naphthalene, etc., in an amount equimolar or more with the alkali (earth) metal and THF, etc., as a solvent.
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