Patent ID: 7468448

Claim:
A method for producing a compound having a configuration represented by the formula (XXVI): or the enantiomer thereof wherein the method comprises deprotecting and cyclizing a compound having a configuration represented by the formula (XXV): or the enantiomer thereof wherein R 10 and R 11 are the same or different and each is independently a hydrogen atom, a lower alkyl group, a lower alkoxyl group or a phenyl group, or R 10 and R 11 are optionally taken together to form an α,ω-alkylene group having 2 to 5 carbon atoms, wherein one of the carbon atoms at positions other than α-position and ω-position is optionally substituted by an oxygen atom or a sulfur atom, with an acid to form a compound having a configuration represented by the formula (XXVI) or the enantiomer thereof, wherein the acid is selected from a group consisting of hydrochloric acid, sulfuric acid, phosphoric acid, methanesulfonic acid, p-toluenesulfonic acid, and a strong acidic ion-exchange resin.