2,2-Difluoro-3-[(2-Methyl-1-oxo-2-propen-1-yl)oxy]pentanoic acid 1,1-diMethylethyl ester

1092693-72-5

920-46-7

1092693-73-6

Example 6: General procedure for the preparation of tert-butyl 2,2-difluoro-3-[(2-methyl-1-oxo-2-propen-1-yl)oxy]pentanoate (1-(tert-butoxycarbonyl)-1,1-difluoro-2-butylmethacrylate): in a 25 mL reactor, 1.50 g (5.6 mmol) of tert-butyl 2,2-difluoro-3-hydroxypentanoate was added sequentially, 15 mL of chloroform, 10 mg of NONFLEX MBP, 1.17 g (11.2 mmol, 2.0 eq.) of methacryloyl chloride and 0.87 g (8.6 mmol, 1.5 eq.) of triethylamine. The reaction mixture was stirred at 55 °C for 24 hours. After completion of the reaction, 15 mL of water was added and extracted once with chloroform. The organic layers were combined and washed sequentially with saturated sodium bicarbonate solution and deionized water, then dried with anhydrous magnesium sulfate. After filtration, the solvent was removed by distillation under reduced pressure to afford 1.57 g of the target product 1-(tert-butoxycarbonyl)-1,1-difluoro-2-butyl methacrylate in 58% purity and 58% yield. The product was characterized by the following data: 1H NMR (CDCl3) δ 6.15 (s, 1H; methylene), 5.62 (m, 1H; methylene), 5.36 (m, 1H; CH-O), 1.93 (s, 3H; CH3), 1.78 (m, 2H; CH2), 1.46 (s, 3H; CH3), 0.95 (t, J = 7.6 Hz. 3H; CH3); 19F NMR (CDCl3) δ -113.15 (dd, J = 7.3 Hz, 261 Hz, 1F), -120.17 (dd, J = 14.6 Hz, 261 Hz, 1F).