Reaction Steps
Cyclopropylmethanol (10.0 g, 138.8 mmol) was treated with n-BuLi (2.5M in hexane 7.4 g, 46 mL, 115.6 mmol) at −15° C. under nitrogen, and the reaction mixture was stirred 1 h at 25° C. To the mixture was added 2-(2,5-difluoro-4-nitro-phenyl)-4-methyl-pentanoic acid ethyl ester (29 g, 96 mmol) in Cyclopropylmethanol (30 mL) dropwise at 25° C. and the reaction mixture stirred for an additional 16 h. Water (100 mL) was added and the reaction mixture was extracted with EtOAc (3×100 mL). The combined organic phases washed with water (3×100 mL), brine (100 mL) and dried (MgSO4). Evaporation of the solvent under reduced pressure gave a brown oil which was purified by column chromatography over silica gel (Heptane-EtOAc gradient) to give 29.5 g, (81%) of 2-(5-cyclopropylmethoxy-2-fluoro-4-nitro-phenyl)-4-methyl-pentanoic acid cyclopropylmethyl ester as a yellow oil. 1H NMR (300 MHz, CDCl3/TMS): δ 7.60 (d, J=9.0 Hz, 1H), 7.15 (d, J=5.7 Hz, 1H), 4.07 (t, J=7.7 Hz, 1H), 4.00-3.80 (m, 4H), 2.01-1.92 (m, 1H), 1.68-1.60 (m, 1H), 1.52-1.43 (m, 1H), 1.34-1.20 (m, 1H), 1.19-1.00 (m, 1H), 0.94 (d, J=6.3 Hz, 6H), 0.65 (d, J=7.7 Hz, 2H), 0.54 (d, J=7.7 Hz, 2H), 0.39 (d, J=4.4 Hz, 2H), 0.25 (d, J=4.4 Hz, 2H); 13C NMR (75 MHz, CDCl3/TMS): δ 172.6, 152.7 (d, 1JCF=243.4 Hz), 148.8, 138.1, 133.3 (d, 2JCF=15.7 Hz), 115.8, 112.6 (d, 2JCF=29.5 Hz), 75.1, 70.0, 42.1, 41.7, 26.1, 22.5, 22.2, 10.0, 9.8, 3.4.
