Réaction #1596944

Équation de réaction

ethanol

bismuth(III) bromide

4-benzyloxy-3-fluorobenzaldehyde

2-vinylpentan-1-ol

→

2-(4-benzyloxy-3-fluorophenyl)-4-bromo-5-propyltetrahydropyran

Solvants

chlorobutane

dichloromethane

Conditions de réaction

Traitement

1. 1
   AutreInsoluble constituents are separated off
2. 2
   Filtrationthe mixture is filtered absorptively (SiO2, CH2Cl2)
3. 3
   ConcentrationThe filtrate is concentrated to dryness
4. 4
   Autrethe residue is purified by column chromatography (SiO2, n-heptane:MTBE=4:1)
5. 5
   AutreThe oil obtained
6. 6
   AutreThe crystals which deposit are collected
7. 7
   Autrerecrystallised again from n-heptane

Mode opératoire

188.0 g (0.79 mol) of 4-benzyloxy-3-fluorobenzaldehyde are initially introduced in 1000 ml of dichloromethane at 0° C. together with 90.0 g (0.79 mol) of 2-vinylpentan-1-ol. 176.0 g (0.39 mol) of bismuth(III) bromide are added in portions, and the mixture is stirred at room temperature for 19 h. Insoluble constituents are separated off, and the mixture is filtered absorptively (SiO2, CH2Cl2). The filtrate is concentrated to dryness, and the residue is purified by column chromatography (SiO2, n-heptane:MTBE=4:1). The oil obtained is taken up in chlorobutane, and the solution is added dropwise to cold ethanol. The crystals which deposit are collected and recrystallised again from n-heptane. In this way, 2-(4-benzyloxy-3-fluorophenyl)-4-bromo-5-propyltetrahydropyran is obtained as a yellowish solid.

Source