Reaction #88834

Reaction equation

4-bromo-2-chlorobenzoic acid methyl ester

tributyl(vinyl)tin

→

2-chloro-4-vinylbenzoic acid

Solvents

THF

Conditions

Workup

1. 1
   OtherThe crude reaction mixture
2. 2
   Concentrationwas then concentrated down
3. 3
   Filtrationfiltered through a pad of celite
4. 4
   Concentrationconcentrated down

Procedure

To a solution of 4-bromo-2-chlorobenzoic acid methyl ester (500 mg, 2 mmol) in THF (15 mL) was added tributyl(vinyl)tin (620 μl, 2.1 mmol) and PdCl2(dppf)-2-DCM (165 mg, 0.2 mmol). The solution was heated to 60° C. for 12 hours. The crude reaction mixture was then concentrated down and taken up in 20 mL EtOAc and 100 mL concentrated KF solution. The reaction stirred at room temperature for 3 hours, filtered through a pad of celite and concentrated down. The residual oil was subjected to flash chromatography (Isco Companion, 40 g SiO2 cartridge, solid loaded SiO2, neat heptanes to EtOAc gradient) to give 2-chloro-4-vinylbenzoic acid as a yellow oil. Amount obtained: 235 mg (60%). LCMS (M/Z): 197 (M+H). 1H NMR (Chloroform-d) δ: 3.93 (s, 3 H) 5.42 (d, J=10.9 Hz, 1 H) 5.86 (d, J=17.6 Hz, 1 H) 6.66 (dd, J=17.6, 10.7 Hz, 1 H) 7.28-7.35 (m, 1 H) 7.43-7.50 (m, 1 H) 7.82 (d, J=8.0 Hz, 1 H).

Source