Reaktion #57415

Reaktionsgleichung

tetrahydrofuran

1,2-dibromoethane

methyl trichloroacetate

chlorotrimethylsilane

→

(2,2-dichloro-1-methoxy-vinyloxy)-trimethylsilane

Ausbeute 106.3%

Lösungsmittel

heptane

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeA 2-liter three-necked flask equipped with a mechanical stirrer
2. 2
   Sonstigethermometer, condenser, pressure equalizing
3. 3
   workup.ADDITIONaddition funnel and an argon inlet
4. 4
   TemperaturThe resulting mixture was heated at
5. 5
   Temperatura gentle reflux for 25 minutes
6. 6
   Temperaturto maintain the reaction temperature at −55 to −60° C. (1 hour required)
7. 7
   workup.ADDITIONAfter the addition
8. 8
   Filtrationfiltered under nitrogen through a Celite 545 pad
9. 9
   WaschenThe filtercake was washed with additional heptane (1×300 ml, 3×200 ml)
10. 10
    EinengenThe filtrate was then concentrated at reduced pressure on a rotary evaporator (approximately 10-15 mm Hg with a 22-27° C. water bath)

Vorschrift

A 2-liter three-necked flask equipped with a mechanical stirrer, thermometer, condenser, pressure equalizing addition funnel and an argon inlet was charged with zinc dust (78.0 g, 1.19 mol) followed by the addition of anhydrous tetrahydrofuran (400 ml). To this mixture was added 1,2-dibromoethane (2 ml) to activate the zinc. The resulting mixture was heated at a gentle reflux for 25 minutes. After cooling to −55° C., a solution of methyl trichloroacetate (100.3 g, 0.565 mol) and chlorotrimethylsilane (80 ml, 0.648 mol) was added at a rate to maintain the reaction temperature at −55 to −60° C. (1 hour required). After the addition was complete, the mixture was allowed to stir at room temperature for approximately 90 minutes. The resulting mixture was diluted with heptane (700 ml) and filtered under nitrogen through a Celite 545 pad. The filtercake was washed with additional heptane (1×300 ml, 3×200 ml). The filtrate was then concentrated at reduced pressure on a rotary evaporator (approximately 10-15 mm Hg with a 22-27° C. water bath) to give crude (2,2-dichloro-1-methoxy-vinyloxy)-trimethylsilane as a dense oil (129.2 g). Quantitative proton NMR indicates this crude material contains 0.389 mol (68.8%) of (2,2-dichloro-1-methoxy-vinyloxy)-trimethylsilane.

Quelle