Reaktion #1285670

Reaktionsgleichung

oxalyl chloride

DMSO

alcohol

N-Acetyl-3-(indol-3-yl)propanol

(carbethoxymethylene)triphenyl phosphorane

NEt3

→

olefin

Ausbeute 56.4%

5-(N-Acetyl-indol-3-yl)pent-2-enoic acid ethyl ester

Ausbeute 56.4%

Lösungsmittel

CH2Cl2

CH2Cl2

ether

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITAfter 30 minutes
2. 2
   SonstigeThe cooling bath was removed
3. 3
   workup.WAITAfter 2.0 hours
4. 4
   Waschenwashed with H2O (2 times), 5% KHSO4 and brine
5. 5
   Trocknendried (MgSO4)
6. 6
   Einengenconcentrated

Vorschrift

To a stirring solution of oxalyl chloride (11.4 mL, 0.13 mol) in CH2Cl2 (440 mL) at -78° C. was added dry DMSO (12.4 mL, 0.17 mol) dropwise. After 5 minutes, gas evolution ceased and the alcohol 4 (19 g, 87 mmol) in CH2Cl2 (40 mL) was added. After 30 minutes, NEt3 (73 mL, 0.52 mol) was added to effect a thick slurry. The cooling bath was removed and the reaction stirred for an additional 15 minutes before adding (carbethoxymethylene)triphenyl phosphorane (33.5 g, 96 mmol). After 2.0 hours, the reaction mixture was diluted with ether and then washed with H2O (2 times), 5% KHSO4 and brine, dried (MgSO4), and concentrated. Flash chromatography (20% ethyl acetate/hexanes) gave the olefin 5 (14 g) as a white solid. TLC Rf=0.54 (60% ethyl acetate/hexanes); 1H NMR (CDCl3) 8.42 (bd, 1H), 7.50 (d, J=7 Hz, 1H), 7.34 (t, J=7 Hz, 1H), 7.28 (t, J=7 Hz, 1H), 7.19 (bs, 1H), 7.03 (dt, J=18 and 7 Hz, 1H), 5.88 (d, J=18 Hz, 1H), 4.19 (q, J=7 Hz, 2H), 2.87 (t, J=7 HZ, 2H), 2.63 (m, 2H), 2.61 (s, 3H), 1.28 (t, J=7 Hz, 3H).

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