反応 #1772041

反応方程式

3-bromobenzaldehyde

potassium tert-butoxide

THF

→

(E)-5-(3-bromophenyl)pent-4-enoic acid

収率 82.0%

溶媒

DMSO

DMSO

反応条件

後処理

1. 1
   workup.WAITAfter several minutes a precipitate was observed
2. 2
   workup.ADDITIONThe solution was poured onto water (120 mL)
3. 3
   洗浄washed with chloroform
4. 4
   抽出extracted with chloroform (3×250 mL)
5. 5
   濃縮The organic phase was concentrated
6. 6
   洗浄Gradient elution from 15-65% B (A=Hexanes

実験手順

A 1M solution of potassium tert-butoxide in THF (80 mL) was added dropwise to (3-carboxypropyl)triphenylphosphoium bromide (17 g, 40 mmol) in anhydrous DMSO (20 mL) under nitrogen at 24° C., and the solution was stirred 30 min before addition of 3-bromobenzaldehyde (4.7 mL, 40 mmol). After several minutes a precipitate was observed and an additional 20 mL of DMSO was added to aid salvation, and the reaction was stirred 18 hours. The solution was poured onto water (120 mL) and washed with chloroform. The aqueous layer was acidified with conc. HCl and extracted with chloroform (3×250 mL). The organic phase was concentrated and applied to a 65 (M) Biotage® silica gel column; Gradient elution from 15-65% B (A=Hexanes; B=EtOAc) over 2 L to give Example 1, (E)-5-(3-bromophenyl)pent-4-enoic acid 8.2 g (82%). 1H NMR (300 MHz, CDCl3) δ 7.45 (t, J=1.5 Hz, 1H), 7.30 (dt, J=7.7, 1.5 Hz, 1H), 7.2-7.16 (m, 1H), 7.12 (t, J=7.7 Hz, 1H), 6.40-6.32 (m, 1H), 6.23-6.14 (m, 1H), 2.52 (s, 4H). RT=2.0 minutes (condition 1); LRMS: Anal. Calcd. for C11H11BrO2: 252.97. found: 252.98 (M−H).

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