Reaktion #456951

Reaktionsgleichung

1-benzyl-4-piperidinone

2,3-dihydro-2,2-dimethylbenzofuran

tetramethylethylenediamine

BuLi

→

7-(1-benzyl-4-hydroxy-4-piperidinyl)-2,3-dihydro-2,2-dimethylbenzofuran

Ausbeute 19.3%

Lösungsmittel

heptane

heptane

hexane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas cooled to -40° C.
2. 2
   Temperaturto warm to room temperature during 3 h
3. 3
   Sonstigeby quench with water
4. 4
   EinengenAfter concentrating the reaction mixture in vacuo dichloromethane (500 ml)
5. 5
   workup.ADDITIONwas added
6. 6
   Waschenby wash with water (3×500 ml)
7. 7
   SonstigeRemoval of solvent in vacuo
8. 8
   Sonstigegave an oil which
9. 9
   Sonstigewas purified by flash chromatography (silica gel, heptane/ethyl acetate/triethylamine 50:48:2)
10. 10
    Sonstigegiving an oil

Vorschrift

A mixture of 2,3-dihydro-2,2-dimethylbenzofuran (25 g) and tetramethylethylenediamine (46 g) in heptane (250 ml) was treated dropwise at room temperature with 1.6 M BuLi in hexane (250 ml). After stirring for 1.5 h at 30-40° C. the mixture was cooled to -40° C. and 1-benzyl-4-piperidinone (32 g) was added dropwise at -40° C. The reaction mixture was allowed to warm to room temperature during 3 h followed by quench with water. After concentrating the reaction mixture in vacuo dichloromethane (500 ml) was added followed by wash with water (3×500 ml). Removal of solvent in vacuo gave an oil which was purified by flash chromatography (silica gel, heptane/ethyl acetate/triethylamine 50:48:2) giving an oil. Addition of heptane gave the product, 7-(1-benzyl-4-hydroxy-4-piperidinyl)-2,3-dihydro-2,2-dimethylbenzofuran as a solid (11 g).

Quelle