Reaktion #2439296

Reaktionsgleichung

triphenylphosphine

11-hydroxyundecyne

carbon tetrabromide

→

11-bromoundecyne

Ausbeute 52.4%

Lösungsmittel

methylene chloride

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITThe reaction was kept at 0° C. for an additional 15 minutes
2. 2
   workup.STIRRINGstirred at room temperature for 3 hours
3. 3
   SonstigeThe methylene chloride was removed in vacuo
4. 4
   workup.ADDITIONThe residue was treated with hexane
5. 5
   Extraktionthe combined organic extract
6. 6
   Einengenwas concentrated in vacuo
7. 7
   SonstigeThe crude product was purified by flash chromatography on silica
8. 8
   Wascheneluting with straight hexane

Vorschrift

To an ice-cold solution of 11-hydroxyundecyne (10 g, 59.4 mmoles) in 400 ml of methylene chloride under argon was added in one portion carbon tetrabromide (40.5 g, 0.1224 mole). The reaction mixture was stirred at 0° C. for 5 minutes and triphenylphosphine (29.43 g, 0.1122 mole) was added. The reaction was kept at 0° C. for an additional 15 minutes and stirred at room temperature for 3 hours. The methylene chloride was removed in vacuo. The residue was treated with hexane and the combined organic extract was concentrated in vacuo. The crude product was purified by flash chromatography on silica, eluting with straight hexane, to give 7.2 g (52%) of 11-bromoundecyne as a colorless oil. Following the procedures of Examples 20 and 39(a), a mixture of salicylaldehyde, 11-bromoundecyne and potassium carbonate in dimethylformamide is reacted to furnish 2-(10-undecynyloxy)benzaldehyde.

Quelle