(Diethylamino)sulfur trifluoride → 4-Fluoro-4-methyl-pent-2-ynoic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 4-hydroxy-4-methyl-pent-2-ynoic acid ethyl ester (4.9 g, 155 mmol) in dichloromethane (30 mL) was cooled to −78° C. and treated with DAST (5.3 g, 161.2 mmol) the reaction mixture was stirred for 2 h at −78° C. then warmed to room temperature and poured over ice. After the ice had melted, the phases were separated and the aqueous phase was extracted with dichloromethane. The combined organic phases were dried (sodium sulfate) and concentrated on a rotary evaporator to provide 5.0 g (100%) of 4-fluoro-4-methyl-pent-2-ynoic acid ethyl ester as a brown oil.

Provenance & Evidence