反应详情

A 500 mL reactor was charged with 24.2 g (370 mmol/1.5 equivalents) of an activated metal zinc and 300 mL of THF (dehydrated), and thereto an ethyl bromodifluoroacetate/THF solution [51.47 g (253.6 mmol/1.0 equivalent) of ethyl bromodifluoroacetate and 80 mL of THF (dehydrated)] was added dropwise. After the dropping, stirring was conducted at room temperature for 20 minutes. Then, a propionaldehyde/THF solution [14.80 g (254.8 mmol/1.0 equivalent) of propionaldehyde and 80 mL of THF (dehydrated)] was added, followed by stirring at room temperature for 30 minutes. Then, water and diisopropyl ether were added to conduct a two-layer separation. The obtained organic layer was washed with diluted hydrochloric acid and water, followed by removing water by magnesium sulfate, conducting a filtration, and distilling diisopropyl ether out, thereby obtaining 41.2 g of the target 2,2-difluoro-3-hydroxypentanoic acid ethyl ester. Upon this, yield was 89%.

1. stirringby stirring at room temperature for 30 minutes
2. customa two-layer separation
3. washThe obtained organic layer was washed with diluted hydrochloric acid and water
4. customby removing water by magnesium sulfate
5. filtrationa filtration
6. distillationdistilling diisopropyl ether out