[CH:1]1([C:6]2[CH:11]=[CH:10][C:9]([OH:12])=[CH:8][CH:7]=2)[CH2:5][CH2:4][CH2:3][CH2:2]1.[OH-].[K+].C1OCCOCCOCCOCCOCCOC1.[CH2:33]([O:35][CH:36]([O:43][CH2:44][CH3:45])[C:37]#[C:38][C:39]([O:41][CH3:42])=[O:40])[CH3:34]>C1COCC1.O>[CH2:44]([O:43][CH:36]([O:35][CH2:33][CH3:34])/[C:37](/[O:12][C:9]1[CH:8]=[CH:7][C:6]([CH:1]2[CH2:2][CH2:3][CH2:4][CH2:5]2)=[CH:11][CH:10]=1)=[CH:38]/[C:39]([O:41][CH3:42])=[O:40])[CH3:45]
To a solution of 2.42 g (15 mmol) of 4-cyclopentylphenol in 50 mL of THF was added 1.12 g (20 mmol) of powdered KOH and 5.28 g (20 mmol) of 18-crown-6. The solution was heated to 50° C. for 15 minutes, whereupon 3.73 g (20 mmol) of methyl 4,4-diethoxy-2-butynoate was added. The mixture was stirred for 30 minutes, then allowed to cool to room temperature. The solution was then poured into water, and extracted 3 times with 40 mL of ethyl acetate. The organic layers were combined, dried (MgSO4) and concentrated. The crude oil was subjected to column chromatography on SiO2. Elution with 20% ethyl acetate-hexane yielded 2.01 g (58%) of an oil, used in the next step without further purification.
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