Reaktion #1596944

Reaktionsgleichung

ethanol

bismuth(III) bromide

4-benzyloxy-3-fluorobenzaldehyde

2-vinylpentan-1-ol

→

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

Lösungsmittel

chlorobutane

dichloromethane

Reaktionsbedingungen

Aufarbeitung

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

Vorschrift

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.

Quelle