1,2-Dibromo-1,1,2,2-tetrafluoroethane → 2-(2-Bromo-thiophen-3-yl)-[1,3]dioxolane

Temperature

-78 °C

A −78° C. solution of the dioxolane of Example 23(a) in dry THF (93 mL, Aldrich) was treated with n-butyllithium (34 mL, 50.7 mmol, 1.49 M/hexanes, Aldrich). The mixture was stirred at −78° C. for 35 minutes and then BrCF2CF2Br (6.1 mL, 51.1 mmol, Aldrich) was added. After 10 minutes, the mixture was allowed to warm to 0° C. and after 30 minutes at 0° C., the mixture was allowed to warm to room temperature. The solution was partitioned between H2O and ether (100 mL each). The layers were separated and the aqueous layer extracted with ether (100 mL). The combined ether solution was washed with 1 M sodium thiosulfate solution (2×100 mL) and brine (100 mL) and then was dried (MgSO4), filtered and evaporated to leave 11.15 g of 2-(2-Bromo-thiophen-3-yl)-[1,3]dioxolane as a yellow oil that was used directly in the next step.

1. waitAfter 10 minutes
2. temperatureto warm to 0° C. and after 30 minutes at 0° C.
3. temperatureto warm to room temperature
4. customThe solution was partitioned between H2O and ether (100 mL each)
5. customThe layers were separated
6. extractionthe aqueous layer extracted with ether (100 mL)
7. washThe combined ether solution was washed with 1 M sodium thiosulfate solution (2×100 mL) and brine (100 mL)
8. dry with materialwas dried (MgSO4)
9. filtrationfiltered
10. customevaporated

ORD record

ord-e1005e79960e4b1f8bef95d219cf3ed5

Source dataset

uspto-grants-2004_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06716864B2