반응 #531238

반응 방정식

α,α'-dibromo-m-xylene

di-isopropylamine

butyl-lithium

t-butyl acetate

→

t-butyl 3-(3-bromomethylphenyl)propionate

용매

tetrahydrofuran

tetrahydrofuran

hexamethylphosphoramide

반응 조건

후처리

1. 1
   workup.ADDITIONTo this solution was added, over 5 minutes
2. 2
   추출the mixture extracted with ether
3. 3
   세척the extract washed with 1 N hydrochloric acid (60 ml)
4. 4
   추출The dried extract
5. 5
   농축was concentrated in vacuo
6. 6
   기타to give a yellow oil which
7. 7
   기타was purified by column chromatography on silica
8. 8
   세척eluting with 1:1 ether

실험 절차

A solution of di-isopropylamine (4.04 g) and butyl-lithium (25 ml, 1.60 M in hexane) in dry tetrahydrofuran (40.0 ml), stirred at -78° under dry nitrogen, was treated over 5 minutes with t-butyl acetate (4.64 g). To this solution was added, over 5 minutes, a solution of α,α'-dibromo-m-xylene (11.60 g) and dry hexamethylphosphoramide (1.42 g) in dry tetrahydrofuran (8.0 ml). The resulting yellow solution was stirred at -78° for 1/2 hour, then allowed to warm to room temperature over 3 hours. Excess ice-water was added, and the mixture extracted with ether, and the extract washed with 1 N hydrochloric acid (60 ml) then water. The dried extract was concentrated in vacuo, to give a yellow oil which was purified by column chromatography on silica, eluting with 1:1 ether:hexane, giving t-butyl 3-(3-bromomethylphenyl)propionate as a colourless oil. Using the method described in the last foregoing paragraph this was converted to the desired diethylester which was used in each of Examples 22 to 25.

출처