반응 #2645

반응 방정식

chloroform

(-)-cis-4-tert-butyldimethylsilyloxy-2-cyclopentenol

chloroform

triethylamine

vinyl acetate

Cis-4-tert-butyldimethylsilyloxy-2-cyclopentenol

→

(-)-acetic acid 4-tert-butyldimethylsilyloxy-cyclopent-2-enyl ester

수율 51.1%

용매

tert-butyl methyl ether

반응 조건

후처리

1. 1
   여과The reaction is then filtered through diatomaceous earth
2. 2
   농축the filtrate is concentrated under vacuum
3. 3
   기타The products are separated by chromatography on silica gel (5% to 20% ethyl acetate/hexane)

실험 절차

Cis-4-tert-butyldimethylsilyloxy-2-cyclopentenol (10.0 g, 46.6 mmol, prepared in example 3a) is dissolved in tert-butyl methyl ether (60 mL, anhydrous). To the solution is added triethylamine (4.5 mL, 32.3 mmol), pancreatin (30 g, available from Sigma Chemical Company), and vinyl acetate (22 mL, 239 mmol). The reaction is allowed to stir for 7 hours at room temperature. The reaction is then filtered through diatomaceous earth and the filtrate is concentrated under vacuum. The products are separated by chromatography on silica gel (5% to 20% ethyl acetate/hexane) to provide (-)-acetic acid 4-tert-butyldimethylsilyloxy-cyclopent-2-enyl ester (B, 6.1 g, 51% yield, 99% ee), [α]D -0.2°, (c=0.52, chloroform) as a yellow oil and (-)-cis-4-tert-butyldimethylsilyloxy-2-cyclopentenol (A, 4.7 g, 47% yield, >99% ee), [α]D -18.6°, (c=1.01, chloroform) as a yellow oil.

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