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

HRID 2553

반응식

HRID 2553 반응식
[C:1]([O:5][C@@H:6]1[CH2:10][C@H:9]([OH:11])[CH:8]=[CH:7]1)([CH3:4])([CH3:3])[CH3:2].C(N(CC)CC)C.[C:19](OC=C)(=[O:21])[CH3:20].C(Cl)(Cl)Cl>COC(C)(C)C>[C:1]([O:5][C@@H:6]1[CH2:10][C@H:9]([O:11][C:19](=[O:21])[CH3:20])[CH:8]=[CH:7]1)([CH3:4])([CH3:2])[CH3:3]

참가 물질

6

반응물 4

HCID 6212ChloroformHCID 7904Vinyl AcetateHCID 8471TriethylamineHCID 11789450cis-4-Tert-butyloxy-cyclopent-2-enol

생성물 1

HCID 11074363(-)-Acetic acid cis-4-tert-butyloxy-cyclopent-2-enyl ester수율 50%

시약·촉매·용매 1

HCID 15413tert-Butyl methyl ether용매

실험 절차

Cis-4-tert-butyloxy-cyclopent-2-enol (485 mg, 3.1 mmol, prepared in example 9) 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 17 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 (10% to 20% ethyl acetate/hexane) to provide (-)-acetic acid cis-4-tert-butyloxy-cyclopent-2-enyl ester (B, 50% yield, 76% ee), [α]D =-10.9°, (c=0.98, chloroform), 1H NMR (CDCl3) δ5.94 (d, 1H, J=5.5 Hz), 5.89 (d, 1H, J=5.5 Hz), 5.46 (appt, 1H, J=5.5 Hz), 4.52 (appt, 1H, J=5.5 Hz), 2.8 (m, 1H), 2.0 (s, 3H), 1.6 (d appt, 1H, J=4.8, 14 Hz), 1.22 (s, 9H); 13C NMR (CDCl3) δ171.2, 138.6, 131.6, 77.4, 77.2, 41, 28.7, 28.6, 21.4; IR (neat) νmax 2976, 1738, 1364, 1242, 1196, 1067, 1020 cm-1 ; CIMS m/e (% relative intensity) 199 (M+H+, 4), 139 (M+H+ -AcOH, 70), 83 (100), and (-)-cis-4-tert-butyloxy-cyclopent-2-enol (A, 194 mg, 40% yield, >98% ee), [α]D 17.2°, (c=1.09, chloroform) as a yellow oil.

후처리

  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 (10% to 20% ethyl acetate/hexane)

출처 및 근거

ORD 기록
ord-1ac771ea14f8470d9583f912bd68a7b3
출처 데이터셋
uspto-grants-1998_03
특허 번호
US05728899

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