Reaction Steps
Following the procedure as described in EXAMPLE 2 and making non-critical variations using 3-(4,5-difluoro-2-hydroxyphenyl)-1-(diphenylmethyl)-1,3-dihydro-2H-indol-2-one to replace 1-(diphenylmethyl)-3-(2-hydroxy-4-methoxy-5-methylphenyl)-1,3-dihydro-2H-indol-2-one, 1′-(diphenylmethyl)-5,6-difluorospiro[1-benzofuran-3,3′-indol]-2′(1′H)-one was obtained (70%) as a colorless solid: mp 213-216° C.; 1H NMR (300 MHz, CDCl3) δ 7.41-7.26 (m, 10H), 7.15-7.12 (m, 1H), 7.08-6.97 (m, 3H), 6.78 (dd, J=10.5, 6.3 Hz, 1H), 6.54 (d, J=8.4 Hz, 1H), 6.44 (dd, J=9.0, 7.8 Hz, 1H), 5.03 (d, J=9.0 Hz, 1H), 4.77 (d, J=9.3 Hz, 1H); 13C NMR (75 MHz, CDCl3) δ 176.8, 156.6 (d, J=11.0 Hz), 151.2 (dd, JC-F=248.2, 14.5 Hz), 145.6 (dd, JC-F=241.5, 13.9 Hz), 141.7, 137.4, 137.1, 131.5, 128.8, 128.8, 128.7, 128.3, 128.3, 128.1, 128.0, 124.2 (dd, J=6.4, 3.3 Hz), 123.8, 123.3, 112.4, 111.5 (dd, J=20.4, 1.6 Hz), 100.1 (d, J=22.4), 80.8, 58.9, 57.5; MS (ES+) m/z 440.2 (M+1).
