[NH2:1][C:2]1[C:7]([F:8])=[C:6]([Cl:9])[N:5]=[C:4]([C:10]([O:12][CH3:13])=[O:11])[C:3]=1I.[CH:15]([Sn](CCCC)(CCCC)CCCC)=[CH2:16]>ClC(Cl)C.Cl[Pd](Cl)([P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)[P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1>[NH2:1][C:2]1[C:7]([F:8])=[C:6]([Cl:9])[N:5]=[C:4]([C:10]([O:12][CH3:13])=[O:11])[C:3]=1[CH:15]=[CH2:16]Methyl 4-amino-6-chloro-5-fluoro-3-iodopicolinate (7.05 g, 21.33 mmol, prepared as described in Epp et al., WO 2013003740 A1) and vinyl tri-n-butyl tin (7.52 mL, 25.6 mmol) were suspended in dichloroethane (71.1 mL) and the mixture was degassed with Argon for 10 min. Bis(triphenylphosphine)palladium(II) chloride (1.497 g, 2.133 mmol) was then added and the reaction mixture was stirred at 70° C. overnight (clear orange solution). The reaction was monitored by GCMS. After 20 h, the reaction mixture was concentrated, adsorbed onto Celite™, and purified by column chromatography (SiO2, hexanes/ethyl acetate gradient) to afford the title compound as a light brown solid (3.23 g, 65.7%): mp 99-100° C.; 1H NMR (400 MHz, CDCl3) δ 6.87 (dd, J=18.1, 11.6 Hz, 1H), 5.72 (dd, J=11.5, 1.3 Hz, 1H), 5.52 (dd, J=18.2, 1.3 Hz, 1H), 4.79 (s, 2H), 3.91 (s, 3H); 19F NMR (376 MHz, CDCl3) δ −138.79 (s); EIMS m/z 230.
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