To a stirred solution of 1-(2,2-dimethylpropanoyl)-2-methyl-N-phenyl-7-(propan-2-yl)indolizine-3-carboxamide (70 mg, 0.19 mmol) in DMF (2.0 mL) is added Triton B (8 μl, 0.02 mmol) followed by methyl acrylate (18 μl, 0.20 mmol). The reaction is stirred for 3 days at 23° C. after which time DBU (0.20 mL, 1.31 mmol) and additional methyl acrylate (0.10 mL, 1.11 mmol) are introduced. The reaction is heated at 50° C. for 18 h and then cooled to 23° C., poured into water, extracted with EtOAc, dried with MgSO4, filtered, and concentrated in vacuo. Purification of the crude by flash chromatography (SiO2, hexanes to 30% EtOAc in hexanes) gives methyl N-{[1-(2,2-dimethylpropanoyl)-2-methyl-7-(propan-2-yl)indolizin-3-yl]carbonyl}-N-phenyl-beta-alaninate (60 mg, 70%).
