Reaktion #2653

Reaktionsgleichung

acetic anhydride

ethyl acetate hexane

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

diethyl ether

→

title compound

Ausbeute 98.0%

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

Ausbeute 98.0%

Lösungsmittel

pyridine

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigethe reaction overnight
2. 2
   workup.ADDITIONDilute
3. 3
   Waschenwash with 3M hydrochloric acid (3×100 mL), saturated sodium bicarbonate (100 mL), brine (100 mL)
4. 4
   Trocknendry over anhydrous magnesium sulfate
5. 5
   Filtrationfilter
6. 6
   Einengenconcentrate under vacuum

Vorschrift

Dissolve (-)-cis-4-tert-butyldimethylsilyloxy-2-cyclopentenol (1 g, 4.67 mmol, prepared in example 10) in pyridine (20 mL) and treat with acetic anhydride (2 mL). Stir the reaction overnight. Dilute the reaction with diethyl ether (100 mL), wash with 3M hydrochloric acid (3×100 mL), saturated sodium bicarbonate (100 mL), brine (100 mL), dry over anhydrous magnesium sulfate, filter and concentrate under vacuum to provide the title compound (1 g, 98% yield) Rf =0.5 (5% ethyl acetate/hexane) [α]20D =+1.3°, (c=1.00, chloroform), 1H NMR (CDCl3)δ5.9 (m, 1H), 5.5 (m, 1H), 4.7 (m, 1H), 2.8 (m, 1H), 2.05 (s, 3H), 1.6 (m, 1H), 0.91 (s, 9H), 0.09 (s, 6H); 13C NMR (CDCl3) δ170.8, 138.8, 131.1, 76.9, 74.8, 41.1, 25.8, 21.1, 18.1, -4.7, -4.6; IR (neat) νmax 2955, 2932, 2859, 1739, 1369, 1240, 1105, 1062, 1049 cm-1 ; CIMS m/e (% relative intensity) 256 (M+H+, 7), 197 (M+H+ --AcOH, 100).

Quelle