Carbon tetrabromide → 3-(2,2-Dibromoethenyl)-2,5-dimethoxytetrahydrofuran

A mixture of Zn powder (1.65 g, 25.0 mmol), triphenylphosphine (6.54 g, 25.0 mmol), and CBr4 (8.30 g, 25.0 mmol) in dry CH2Cl2 (40 mL) was stirred at ambient temperature. After 24 hours, 2,5-dimethoxy-tetrahydrofuran-3-carboxaldehyde (2.00 g, 12.5 mmol) was added and an exothermic reaction ensued. After 30 minutes, pet ether (100 mL) was added and the resultant upper layer separated. The lower layer was twice diluted with CH2Cl2 (50 mL) and pet ether (50 mL), and the upper layer reserved. The combined upper layers were combined, passed through a pad of SiO2, and concentrated under reduced pressure at 30° C. or below to give 2.18 g (55%) of 3-(2,2-dibromoethenyl)-2,5-dimethoxytetrahydrofuran as a volatile colorless oil, which was a mixture of diastreomers by 1H NMR and used immediately without further purification.

1. customan exothermic reaction
2. waitAfter 30 minutes
3. customthe resultant upper layer separated
4. additionThe lower layer was twice diluted with CH2Cl2 (50 mL) and pet ether (50 mL)
5. concentrationconcentrated under reduced pressure at 30° C. or below

ORD-Eintrag

ord-70ff169213d541b0ba03153e63bc0a69

Quelldatensatz

uspto-grants-1999_12

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06008243