Acetone → HCID 11310024, compound

Temperature

-60 °C

Dissolve the trisylhydrazone derivative of acetone (8.0 g, 23.7 mmol) in 70 mL of DME at −78° C. Add butyllithium (29.6 mL, 47.4 mmol, 2 eq.) dropwise. Stir the mixture at −60° C. for 10 min, cool to −78° C., then add 1-iodo-3-methylbutane (3.13 mL, 23.7 mmol, 1 eq.) dropwise. Stir the mixture overnight at −65° C., cool to −78° C., then treat successively with TMEDA (12.5 mL, 82.3 mmol, 3.5 eq.), then BuLi (16.3 mL, 26.1 mmol, 1.1 eq.). Stir this mixture for 20 min at −78° C., then heat to 0° C. and maintain at this temperature until evolution of nitrogen ceases (˜5 min). Then cool the reaction mixture to −78° C. and add 1,2-dibromoethane (6.6 mL, 35.5 mmol, 1.5 eq). Heat the mixture slowly to 0° C., then hydrolyze with aqueous NaCl. After extraction (Et2O) and washing (twice with water then once with saturated NaCl solution), dry the solution over MgSO4 and evaporate. Then chromatograph the residue on silica gel (eluent: cyclohexane). The brominated derivative (E)-2-bromo-6-methyl-hept-2-ene is obtained in the form of a slightly yellow oil (2.5 g, 57%).

1. temperaturecool to −78° C.
2. stirringStir the mixture overnight at −65° C.
3. temperaturecool to −78° C.
4. stirringStir this mixture for 20 min at −78° C.
5. temperatureheat to 0° C.
6. temperaturemaintain at this temperature until evolution of nitrogen ceases (˜5 min)
7. temperatureThen cool the reaction mixture to −78° C.
8. temperatureHeat the mixture slowly to 0° C.
9. extractionAfter extraction (Et2O)
10. washwashing (twice with water
11. dry with materialonce with saturated NaCl solution), dry the solution over MgSO4
12. customevaporate

ORD record

ord-2c6d2dd66fd0431aa7245b14a21e4034

Source dataset

uspto-grants-2008_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07396953B2