Isopropylmagnesiumchloride-LiCl complex (1.30 M in THF, 155.0 mL, 0.0715 mol) under nitrogen was cooled to 0-5° C., and 2,3-difluorobromobenzene (13.8 g, 0.0715 mol, 1.50 equiv.) was added while T<10° C. After 1 h at 0-5° C., a solution of 1-morpholino-2-(1-(trityloxy)but-3-en-2-yloxy)ethanone (21.8 g, 0.048 mol, 1.0 equiv.) in THF (2.0 vols) was added while T<10° C. The reaction mixture was stirred for 2.5 h and monitored for consumption of 1-morpholino-2-(1-(trityloxy)but-3-en-2-yloxy)ethanone (target>97%). The reaction mixture was quenched by charging into cold sat. aq. NH4Cl (110 mL) and water (33 mL) while T<20° C. 2-Methoxy-2-methylpropane (218 mL) was added and the layers were separated. The organics were washed with sat. aq. NH4Cl (65 mL) and 18% aq. NaCl (44 mL). The organics were concentrated under vacuum T<25° C. to a light yellow oil (21.6 g). 1H NMR (500 MHz, CDCl3) δ ppm 7.70-7.64 (m, 1H), 7.47-7.42 (m, 6H), 7.37-7.30 (m, 1H), 7.30-7.25 (m, 6H), 7.24-7.19 (m, 3H), 7.19-7.13 (m, 1H), 5.84-5.71 (m, 1H), 5.30 (d, J=17.3 Hz, 1H), 5.25 (d, J=10.4 Hz, 1H), 4.78 (dd, J=17.7, 3.1 Hz, 1H), 4.70 (dd, J=17.7, 3.1 Hz, 1H), 4.03 (dd, J=11.8, 6.5 Hz, 1H), 3.35 (dd, 1=9.8, 6.4 Hz, 1H), 3.18 (dd, J=9.8, 4.6 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ ppm 194.15 (dd, JCF=4.9, 2.4 Hz), 150.77 (dd, JCF=250.3, 14.1 Hz), 150.29 (dd, JCF=256.4, 13.9 Hz), 143.98, 135.34, 128.75, 127.76, 126.95, 125.70 (d, JCF=12.0 Hz), 125.16 (d, JCF=3.5 Hz), 124.55 (dd, JCF=6.4, 4.2 Hz), 121.62 (d, JCF=17.6 Hz), 118.83, 86.78, 81.35, 74.98 (d, JCF=9.5 Hz), 66.71.
