반응 #51263

반응 방정식

n-butyllithium

tetramethylethylenediamine

diiodomethane

4,4-dimethylchroman

→

4,4-dimethyl-8-iodochroman

용매

ethyl ether

water

ethyl ether

반응 조건

후처리

1. 1
   온도Cooling
2. 2
   기타is carried out to 0° C.
3. 3
   온도the preceding solution, cooled beforehand to −78° C.
4. 4
   workup.ADDITIONis introduced
5. 5
   기타to return to room temperature
6. 6
   workup.STIRRINGstirred for 12 hours
7. 7
   추출extracted with ethyl ether
8. 8
   기타the organic phase is separated
9. 9
   건조dried over magnesium sulphate
10. 10
    기타evaporated
11. 11
    기타The residue obtained
12. 12
    기타is purified by chromatography on a silica column
13. 13
    세척eluted with heptane
14. 14
    기타After evaporating the solvents, 1.30 g (37%) of the expected compound
15. 15
    기타are collected in the form of a pale-yellow oil

실험 절차

2.00 g (12.3 mmol) of 4,4-dimethylchroman and 30 ml of ethyl ether are introduced into a three-necked flask under argon. 2.4 m (15.9 mmol) of tetramethylethylenediamine (TMEDA) are added dropwise, the mixture is cooled to −78° C. and 5.9 ml (14.8 mmol) of n-butyllithium (2.5M in hexane) are added dropwise. The temperature is allowed to return to −20 °C. over two hours and then to room temperature and the mixture is stirred for 12 hours. 1.3 ml (16.0 mmol) of diiodomethane and 15 ml of ethyl ether are introduced into another three-necked flask under argon. Cooling is carried out to 0° C. and the preceding solution, cooled beforehand to −78° C., is introduced, then the reaction mixture is allowed to return to room temperature and stirred for 12 hours. The reaction mixture is poured into water and extracted with ethyl ether and the organic phase is separated by settling, dried over magnesium sulphate and evaporated. The residue obtained is purified by chromatography on a silica column eluted with heptane. After evaporating the solvents, 1.30 g (37%) of the expected compound are collected in the form of a pale-yellow oil.

출처