2-Chloropropane → HCID 13407681, compound

Temperature

-78 °C

20.2 g (0.83 mole) of magnesium and 300 ml of ethyl ether were placed in a 1,000 ml three-neck round bottom flask, and 65 g (0.82 mole) of 2-chloropropane was slowly added thereto, to prepare a Grignard solution. Meanwhile, 114 g (0.40 mole) of titanium (IV) isopropoxide and 40.0 g (0.40 mole) of vinyltrimethylsilane were placed in another 1,000 ml three-neck round bottom flask cooled to −78° C., and the above-prepared Grignard solution was gradually added thereto for 30 minutes. The reaction solution thus obtained was warmed to −50° C. and then vigorously stirred for 2 hours. 36 g (0.4 mole) of ethyl acetate was gradually added over 30 min, while the reaction solution was maintained at −50° C. The reaction solution was warmed to −20° C., vigorously stirred for 1 hour, warmed to 0° C., and then vigorously stirred for another 1 hour. Finally, the reaction solution was warmed to room temperature and 70 mL of saturated brine was added to the solution. The resulting solution was filtered through Celite which was then thoroughly washed once more with 20 mL of ether. The filtrate thus obtained was dried over anhydrous magnesium sulfate (MgSO4) and was concentrated by the evaporation of solvent under reduced vacuum at a low temperature of 30° C. or less. The resulting concentrate was distilled (35-50° C./0.1 mmHg) under vacuum to obtain 27.8 g (0.21 mole, yield: 52%) of 1-methyl-1-hydroxy-2-(trimethylsilyl)cyclopropane as a mixture of two isomers, i.e., trans and cis isomers. Although these isomers may be used directly without any further purification, the trans and cis isomers were separated by silica gel chromatography for structural analysis. The analysis results ascertained that the trans and cis isomers are present in a ratio of about 3:1.

1. customto prepare a Grignard solution
2. additionthe above-prepared Grignard solution was gradually added
3. customThe reaction solution thus obtained
4. temperaturewas warmed to −50° C.
5. temperaturewas maintained at −50° C
6. temperatureThe reaction solution was warmed to −20° C.
7. stirringvigorously stirred for 1 hour
8. temperaturewarmed to 0° C.
9. stirringvigorously stirred for another 1 hour
10. temperatureFinally, the reaction solution was warmed to room temperature
11. filtrationThe resulting solution was filtered through Celite which
12. washwas then thoroughly washed once more with 20 mL of ether
13. customThe filtrate thus obtained
14. dry with materialwas dried over anhydrous magnesium sulfate (MgSO4)
15. concentrationwas concentrated by the evaporation of solvent under reduced vacuum at a low temperature of 30° C. or less
16. concentrationThe resulting concentrate
17. distillationwas distilled (35-50° C./0.1 mmHg) under vacuum

ORD record

ord-6fb1360f47474f219c1f68088f2e6016

Source dataset

uspto-grants-2012_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08314051B2