Chloroform → (-)-Acetic acid cis-4-benzyloxy-cyclopent-2-enyl ester

HRID 2555

Reaktionsgleichung

Reaktionsgleichung von HRID 2555
[CH2:1]([O:8][C@@H:9]1[CH2:13][C@H:12]([OH:14])[CH:11]=[CH:10]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C(N(CC)CC)C.[C:22]([O:25][CH:26]=[CH2:27])(=[O:24])[CH3:23].C(Cl)(Cl)Cl>COC(C)(C)C>[CH2:1]([O:8][C@@H:9]1[CH2:13][C@H:12]([OH:14])[CH:11]=[CH:10]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[CH2:1]([O:8][C@@H:9]1[CH2:13][C@H:26]([O:25][C:22](=[O:24])[CH3:23])[CH:27]=[CH:10]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Komponenten

7

Edukt 4

HCID 6212Chloroform2×HCID 7904Vinyl AcetateHCID 8471TriethylamineHCID 15812323(1S,4R)-4-(Benzyloxy)cyclopent-2-en-1-ol

Produkt 2

HCID 15812323(1S,4R)-4-(Benzyloxy)cyclopent-2-en-1-olAusbeute 29 %HCID 86752290(-)-Acetic acid cis-4-benzyloxy-cyclopent-2-enyl esterAusbeute 70 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 15413tert-Butyl methyl etherLösungsmittel

Versuchsvorschrift

Cis-4-benzyloxy-cyclopent-2-enol (500 mg, prepared in example 16) is dissolved in tert-butyl methyl ether (8.6 mL, anhydrous). To the solution is added triethylamine (0.7 eq), pancreatin (3 wt eq, available from Sigma Chemical Company), and vinyl acetate (5 eq). 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 (20% ethyl acetate/hexane) to provide (-)-cis-4-benzyloxy-cyclopent-2-enol (A) (147 mg, 29% yield) [α]20D -12°, (c=1.09, chloroform), and (-)-acetic acid cis-4-benzyloxy-cyclopent-2-enyl ester (B) (427 mg, 70% yield),[α]20D =-5.2°, (c=0.97, chloroform), 1 H NMR (CDCl3) δ 7.3 (m, 5H), 6.13 (d, 1H, J=5 Hz), 5.99 (d, 1H, J=5 Hz), 5.5 (m, 1H), 4.59 (d, 1H, J=11.8 Hz), 4.54 (d, 1H, J=11.8 Hz), 4.5 (m, 1H), 2.78 (d appt, 1H, J=7.2, 14.3 Hz), 2.05 (s, 3H), 1.76 (d appt, 1H, J=4.4, 14.3 Hz); 13C NMR (CDCl3) δ171.1, 138.5, 136.4, 133.1, 128.7, 128, 127.9, 81.4, 77.1, 71.2, 37.8, 21.4.

Aufarbeitung

  1. filtrationThe reaction is then filtered through diatomaceous earth
  2. concentrationthe filtrate is concentrated under vacuum
  3. customThe products are separated by chromatography on silica gel (20% ethyl acetate/hexane)

Quellen und Nachweise

ORD-Eintrag
ord-443e36063c0a47edae71957a9c2af350
Quelldatensatz
uspto-grants-1998_03
Patentnummer
US05728899

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