Реакция #51263

Уравнение реакции

n-butyllithium

tetramethylethylenediamine

diiodomethane

4,4-dimethylchroman

→

4,4-dimethyl-8-iodochroman

Растворители

ethyl ether

water

ethyl ether

Условия реакции

Обработка

1. 1
   ТемператураCooling
2. 2
   Другоеis carried out to 0° C.
3. 3
   Температураthe preceding solution, cooled beforehand to −78° C.
4. 4
   workup.ADDITIONis introduced
5. 5
   Другоеto return to room temperature
6. 6
   workup.STIRRINGstirred for 12 hours
7. 7
   Экстракцияextracted with ethyl ether
8. 8
   Другоеthe organic phase is separated
9. 9
   Сушкаdried over magnesium sulphate
10. 10
    Другоеevaporated
11. 11
    ДругоеThe residue obtained
12. 12
    Другоеis purified by chromatography on a silica column
13. 13
    Промывкаeluted with heptane
14. 14
    ДругоеAfter evaporating the solvents, 1.30 g (37%) of the expected compound
15. 15
    Другоеare collected in the form of a pale-yellow oil

Методика

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.

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