Reaction Steps
To a solution of 2-(3-chloro-5-cyclopropylmethoxy-4-iodo-phenyl)-4-methyl-pentanoic acid cyclopropylmethyl ester (0.27 g, 0.57 mmol) in DME (anhydrous, 10 mL) under argon atmosphere were added 5-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-benzo[1,2,5]oxadiazole (0.15 g, 0.61 mmol), CsF (0.2 g, 1.32 mmol), and [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium (II) (0.021 g, 0.029 mmol, need 0.06 mmol to complete the reaction!). The reaction mixture was refluxed for 18 h (oil bath, 100° C.). A mixture water/EtOAc (15 mL/15 mL) was added and the layers were separated. The organic phase was dried over MgSO4, then evaporated to give a crude yellow oil, which was purified by silica gel gradient column chromatography using Heptane-EtOAc (20:1-9:1) to give 2-(4-benzo[1,2,5]oxadiazol-5-yl-3-chloro-5-cyclopropylmethoxy-phenyl)-4-methyl-pentanoic acid cyclopropylmethyl ester (0.11 g, 41%) of as a yellowish oil. 1H NMR (300 MHz, CDCl3/TMS): δ 7.83 (d, J=9.3 Hz, 1H), 7.77 (s, 1H), 7.36-7.33 (m, 1H), 7.11 (s, 1H), 6.91 (s, 1H), 4.02-3.81 (m, 4H), 3.67 (t, J=7.7 Hz, 1H), 2.03-1.96 (m, 1H), 1.74-1.65 (m, 1H), 1.60-1.45 (m, 1H), 1.20-1.05 (m, 2H), 0.96 (d, J=6.3 Hz, 6H), 0.57-0.47 (m, 4H), 0.28 (br s, 2H), 0.19 (br s, 2H). 13C NMR (75 MHz, CDCl3/TMS): δ 173.4, 157.0, 149.2, 148.3, 142.0, 138.7, 135.4, 133.5, 126.4, 121.6, 117.4, 114.9, 110.6, 73.4, 69.8, 49.8, 42.8, 26.1, 22.5, 22.4, 10.0, 9.8, 3.3, 3.1
