Réaction #65796

Équation de réaction

1,2-dibromocyclopentene

4-methylthiophenylboronic acid

Na2CO3

→

1-(2-bromocyclopenten-1-yl)-4-(methylthio)benzene

Rendement 32.6%

Solvants

toluene

ethanol

Conditions de réaction

Traitement

1. 1
   Températureat reflux overnight
2. 2
   Concentrationconcentrated in vacuo
3. 3
   workup.DISSOLUTIONThe residue was dissolved in ethyl acetate
4. 4
   Lavagewashed with water
5. 5
   Séchagedried (MgSO4)
6. 6
   AutrePurification by silica gel chromatography (Waters Prep-500) with hexane

Mode opératoire

Under nitrogen, 36.4 g (161 mmol) of 1,2-dibromocyclopentene (Aldrich) was reacted with 18.0 g (107 mmol) of 4-methylthiophenylboronic acid (Step 1) in 550 mL of toluene, 365 mL of ethanol, and 235 mL of 2M Na2CO3 in the presence of 6.0 g (5 mol %) of Pd(PPh3)4. The reaction was vigorously stirred at reflux overnight and concentrated in vacuo. The residue was dissolved in ethyl acetate and washed with water, dried (MgSO4), and reconcentrated. Purification by silica gel chromatography (Waters Prep-500) with hexane gave 9.39 g (22%) of 1-(2-bromocyclopenten-1-yl)-4-(methylthio)benzene (38 in Synthetic Scheme X when R5 =SCH3 and R1, R2, R3, R4, R6, and R7 =H) as a solid: mp 52°-54° C.; NMR (CDCl3) d 1.98-2.09 (m, 2H), 2.50 (s, 3H), 2.70-2.78 (m, 2H), 2.80-2.89 (m, 2H), 7.24 (d, J=8 Hz, 2H), 7.55 (d, J=8 Hz, 2H).

Source