Oxalyl chloride → (S)-2-(4-fluorophenyl)pent-4-enoyl chloride

Participants

Reaction Steps

Combine (S)-2-(4-fluorophenyl)pent-4-enoic acid (3.61 g, 18.6 mmol), dichloromethane (20 mL), and dimethylformamide (2 drops). Add oxalyl chloride (1.94 mL, 22.3 mmol). After 2 hours, evaporate in vacuo to give (S)-2-(4-fluorophenyl)pent-4-enoyl chloride. Combine with toluene (10 mL) and slowly add, with vigorous stirring, to a cooled (ice bath) aqueous solution of methylamine (4 mL, 40%). After 1 hour, partition the reaction mixture between water and dichloromethane. Separate the layers, extract the organic layer with a saturated aqueous sodium bicarbonate solution. Dry the organic over MgSO4, filter, and evaporate in vacuo to give a residue. Triturate the residue with hexane to give a solid. Collect the solid by filtration and dry to give (S)-2-(4-fluorophenyl)pent-4-enoic acid, N-methyl amide: mp; 104-105° C. Rf=0.42 (silica gel, 50% ethyl acetate/hexane).

Provenance & Evidence