[C:1]1([CH3:11])[CH:6]=[CH:5][C:4]([S:7](Cl)(=[O:9])=[O:8])=[CH:3][CH:2]=1.[CH3:12][C:13]12[O:20][C:17]([CH3:21])([CH:18]=[CH:19]1)[CH2:16][CH:15]([OH:22])[CH2:14]2.Cl>N1C=CC=CC=1>[C:1]1([CH3:11])[CH:6]=[CH:5][C:4]([S:7]([O:22][CH:15]2[CH2:16][C:17]3([CH3:21])[O:20][C:13]([CH3:12])([CH:19]=[CH:18]3)[CH2:14]2)(=[O:9])=[O:8])=[CH:3][CH:2]=1para-Toluenesulfonyl chloride (15.5 g,) was added portionwise over 20 minutes to an ice-cold stirred solution of 1,5-dimethyl-8-oxabicyclo[3.2.1]oct-6-en-3-ol (10.0 g,) in dry pyridine (75 ml). The reaction mixture was stirred at 0° C. for 0.5 hour, allowed to stand in a refrigerator (0° C.) for 72 hours, and poured into a mixture of 80 ml concentrated hydrochloric acid and 100 g of ice. After stirring for 10 minutes, the precipitated solid was filtered. The collected solid dissolved methylene chloride was dried (MgSO4), filtered and concentrated to give 17.6 g (88%) of the desired product, m.p. 75°-77° C., as a 70:30 mixture of epimers.
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