[Br-].[CH:2]1([Zn+])[CH2:5][CH2:4][CH2:3]1.Br[C:8]1[CH:17]=[CH:16][C:11]([C:12]([O:14][CH3:15])=[O:13])=[C:10]([CH3:18])[CH:9]=1.C(Cl)Cl>C1C=CC(P(C2C=CC=CC=2)[C-]2C=CC=C2)=CC=1.C1C=CC(P(C2C=CC=CC=2)[C-]2C=CC=C2)=CC=1.Cl[Pd]Cl.[Fe+2]>[CH:2]1([C:8]2[CH:17]=[CH:16][C:11]([C:12]([O:14][CH3:15])=[O:13])=[C:10]([CH3:18])[CH:9]=2)[CH2:5][CH2:4][CH2:3]1Cyclobutylzinc(II) bromide (50 mL, 0.5 M in THF, 25.0 mmol) was added to a mixture of methyl 4-bromo-2-methylbenzoate (compound 6.1, 5.2 g, 22.7 mmol) and PdCl2(dppf).CH2Cl2 (1.85 g, 2.27 mmol). The mixture was degassed and the flask was filled with argon through a balloon. The mixture was heated at 65° C. under argon for 24 hours, then cooled to 0° C. and carefully quenched with water (10 mL). The mixture was diluted with EtOAc (200 mL) and washed with water then brine, dried (Na2SO4), filtered, and concentrated under reduced pressure. The residue was purified using silica gel column chromatography (hexanes:EtOAc 30:1 to 20:1) to yield the title compound as a clear oil (4.1 g, 89%). 1H NMR (400 MHz, CDCl3) δ 7.86 (d, 1H), 7.12-7.02 (m, 2H), 3.88 (s, 3H), 3.59-3.48 (m, 1H), 2.59 (s, 3H), 2.35 (m, 2H), 2.22-1.96 (m, 3H), 1.86-1.84 (m, 1H).
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