2-[2-(2-Chloro-phenoxy)-3-ethoxycarbonyl-allylamino]-5,5,5-trifluoro-4-trifluoromethyl-pentanoic acid methyl ester → 2-[4-(2-Chloro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-5,5,5-trifluoro-4-trifluoromethyl-pentanoic acid methyl ester

A solution of 2-[2-(2-chloro-phenoxy)-3-ethoxycarbonyl-allylamino]-5,5,5-trifluoro-4-trifluoromethyl-pentanoic acid methyl ester (144 mg, 0.29 mmol) in acetonitrile (2 mL) was placed in a sealed microwave reaction tube and heated in a microwave reactor at 180° C. for 3 h. The mixture was cooled to room temperature and concentrated in vacuo with silica gel (1.2 g). Purification by Biotage flash chromatography (AnaLogix 25 g column, 16% ethyl acetate/hexanes to 33% ethyl acetate/hexanes) afforded 2-[4-(2-chloro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-5,5,5-trifluoro-4-trifluoromethyl-pentanoic acid methyl ester (52 mg, 7% over two steps) as an amber oil: HR-ES-MS m/z calculated for C17H14NO4ClF6 [M+H]+ 446.0589, observed 446.0588.