تفاعل #88818

معادلة التفاعل

5-bromo-1-pentene

sulfuric acid

ethyl formate

MeTHF

5-bromo-1-pentene

5-bromo-1-pentene

magnesium

MeTHF

→

2-allylcyclopentanol

ظروف التفاعل

المعالجة

1. 1
   workup.ADDITIONwas added to the addition funnel
2. 2
   أخرىthe reaction
3. 3
   workup.ADDITIONAfter the addition
4. 4
   درجة الحرارةwas cooled to room temperature
5. 5
   درجة الحرارةThe mixture was cooled to about 0° C.
6. 6
   workup.ADDITIONslowly the Grignard L was added into the flask over 3 hours
7. 7
   workup.ADDITIONUpon complete addition
8. 8
   درجة الحرارةto warm to room temperature
9. 9
   workup.STIRRINGthe reaction was stirred for about 12 hours
10. 10
    درجة الحرارةThe mixture was then cooled to about 0° C.
11. 11
    workup.STIRRINGThe slurry was stirred for 30 minutes after which the salts
12. 12
    workup.DISSOLUTIONwere dissolved
13. 13
    ترشيحThe mixture was then polished filtered
14. 14
    أخرىThe biphasic mixture was separated
15. 15
    غسيلthe organic layer was then washed twice with 10 wt. % sodium bicarbonate (10 volumes) and once with water (10 volumes)
16. 16
    تركيزThe organic layer is concentrated under reduced pressure at about 0° C.

الإجراء التجريبي

To a reaction vessel was added magnesium turnings (2.45 equivalents) and MeTHF (8 volumes). The flask was then sparged with nitrogen and 5-bromo-1-pentene (2.4 equivalents) was added to the addition funnel. The mixture was heated to about 60° C. and 0.05 volumes of 5-bromo-1-pentene were dripped into the mixture to initiate the reaction. Once the reaction initiated, the remaining portion of 5-bromo-1-pentene was slowly added into the flask over about 3 hours. After the addition, the reaction was allowed to stir at about 60° C. for about 1 hour after which Grignard L was cooled to room temperature. In a separate flask was added ethyl formate (1.0 equivalent) and titanium isopropoxide (0.5 equivalents) in MeTHF (2 volumes) under nitrogen. The mixture was cooled to about 0° C. and slowly the Grignard L was added into the flask over 3 hours. Upon complete addition, the reaction mixture was allowed to warm to room temperature and the reaction was stirred for about 12 hours. The mixture was then cooled to about 0° C. and 4M sulfuric acid (10 volumes) was added slowly. The slurry was stirred for 30 minutes after which the salts were dissolved. The mixture was then polished filtered. The biphasic mixture was separated and the organic layer was then washed twice with 10 wt. % sodium bicarbonate (10 volumes) and once with water (10 volumes). The organic layer is concentrated under reduced pressure at about 0° C. to obtain crude 2-allylcyclopentanol M. 1H NMR (400 MHz, CDCl3): δ 5.53-5.43 (m, 1H), 4.76-4.70 (m, 1H), 4.65-4.59 (m, 1H), 2.90-2.86 (m, 1H), 1.75 (br s, 1H), 1.65-1.51 (m, 2H), 0.69-0.59 (m, 1H), 0.40-0.35 (m, 1H), 0.05-0.01 (m, 1H).

المصدر