Sulfuric Acid → 2-(Prop-2-en-1-yl)cyclopentan-1-ol

Temperature

60 °C

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).

1. additionwas added to the addition funnel
2. customthe reaction
3. additionAfter the addition
4. temperaturewas cooled to room temperature
5. temperatureThe mixture was cooled to about 0° C.
6. additionslowly the Grignard L was added into the flask over 3 hours
7. additionUpon complete addition
8. temperatureto warm to room temperature
9. stirringthe reaction was stirred for about 12 hours
10. temperatureThe mixture was then cooled to about 0° C.
11. stirringThe slurry was stirred for 30 minutes after which the salts
12. dissolutionwere dissolved
13. filtrationThe mixture was then polished filtered
14. customThe biphasic mixture was separated
15. washthe organic layer was then washed twice with 10 wt. % sodium bicarbonate (10 volumes) and once with water (10 volumes)
16. concentrationThe organic layer is concentrated under reduced pressure at about 0° C.

ORD record

ord-22325a8cc5604160b80a69b7b3e8d46d

Source dataset

uspto-grants-2016_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09440991B2