Reaktion #2075721

Reaktionsgleichung

1-chloro-3-fluoro-2-(1-fluoroethyl)benzene

n-butyllithium

diisopropylamine

2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

→

title compound

Ausbeute 94.0%

2-(4-Chloro-2-fluoro-3-(1-fluoroethyl)phenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

Ausbeute 94.0%

Lösungsmittel

THF

hydrochloric acid

tetrahydrofuran THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwarmed to 0° C. for 20 m
2. 2
   Temperaturcooled back to −78° C. for 20 m
3. 3
   Sonstigeat −78° C.
4. 4
   workup.STIRRINGThe resulting dark brown solution was stirred at −78° C. for 2 h
5. 5
   Temperaturthe brown solution was slowly warmed to 23° C. over 20 h
6. 6
   Extraktionextracted with dichloromethane three times
7. 7
   SonstigeThe combined organic layers were dried
8. 8
   Filtrationfiltered
9. 9
   Einengenconcentrated by rotary evaporation

Vorschrift

A 2.5 M solution of n-butyllithium (13 mL, 33 mmol) was added to a stirred solution of diisopropylamine (5.0 mL, 35 mmol) in tetrahydrofuran THF (50 mL) at −78° C. The resulting colorless solution was stirred at −78° C. for 20 m, warmed to 0° C. for 20 m, and then cooled back to −78° C. for 20 m. A solution of 1-chloro-3-fluoro-2-(1-fluoroethyl)benzene (4.8 g, 27 mmol, 1.0 equiv) in THF (20 mL) at −78° C. was transferred to the base solution via cannula. The resulting dark brown solution was stirred at −78° C. for 2 h. 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (8.3 mL, 41 mmol, 1.5 equiv) was added and the brown solution was slowly warmed to 23° C. over 20 h. The reaction mixture was diluted with 0.1M hydrochloric acid (300 mL) and extracted with dichloromethane three times. The combined organic layers were dried, filtered and concentrated by rotary evaporation to afford the title compound as a brown oil that solidified into a semi-solid upon standing (7.7 g, 94% yield). 1H NMR (300 MHz, CDCl3) δ 7.62 (m, 1H), 7.17 (m, 1H), 6.13 (dq, 1H, J=6, 46 Hz), 1.75 (ddd, 3H, J=1, 7, 23 Hz), 1.36 (s, 12 H).

Quelle