HCID 68778166, compound → HCID 59853565, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of 4,4-Difluoro-pyrrolidine-2-carboxylic acid allyl ester trifluoroacetic acid salt (Example 14d, 6.13 g, 20.08 mmol) in anhydrous tetrahydrofuran (300 mL) was added manganese(IV) dioxide and the reaction mixture was heated at 80° C. for 4 h. The mixture was filtered over Celite, and was washed with hot and then cold tetrahydrofuran. The filtrate was concentrated in vacuo to give a dark orange oil. The oil was dissolved in ethyl acetate and the organic layer was washed with saturated aqueous sodium bicarbonate solution. The solvent was removed in vacuo to give an orange oil, which was purified by flash column chromatography (Merck silica gel 60, 40-63 μm, 30% ethyl acetate in hexanes) to afford the desired product, 4-fluoro-1H-pyrrole-2-carboxylic acid allyl ester (3.01 g, 17.80 mmol, 88.7% yield) as a yellow oil. 1H NMR (400 MHz, CDCl3) δ: 4.77 (2H, d, J=5.7 Hz), 5.29 (1H, d, J=10.2 Hz), 5.38 (1H, d, J=15.9 Hz), 5.94-6.04 (1H, m), 6.64-6.65 (1H, m), 6.72-6.74 (1H, m), 8.91 (1H, bs).

Provenance & Evidence