Reaction Steps
Following the procedure as described in EXAMPLE 9 and making non-critical variations using 1-bromo-3-methylbutane to replace 2-(bromomethyl)-5-(trifluoromethyl)furan, and 5,6-difluorospiro[1-benzofuran-3,3′-indol]-2′(1′H)-one to replace 3-methylspiro[furo[3,2-f][1,2]benzisoxazole-5,3′-indol]-2′(1′H)-one, 5,6-difluoro-1′-(3-methylbutyl)spiro[1-benzofuran-3,3′-indol]-2′(1′H)-one was obtained (96%) as a pale yellow oil: 1H NMR (300 MHz, CDCl3) δ 7.34 (t, J=7.7 Hz, 1H), 7.16-7.04 (m, 2H), 6.93 (d, J=7.8 Hz, 1H), 6.77 (dd, J=10.3, 6.3 Hz, 1H), 6.50 (t, J=8.5 Hz, 1H), 4.95 (d, J=9.1 Hz, 1H), 4.70 (d, J=9.1 Hz, 1H), 3.88-3.67 (m, 2H), 1.72-1.60 (m, 3H), 1.01 (d, 6.2 Hz, 6H); 13C NMR (75 MHz, CDCl3) δ176.3, 156.6 (d, JC-F=11.0 Hz), 151.1 (dd, JC-F=248.1, 14.5 Hz), 145.6 (dd, JC-F=241.3, 14.0 Hz), 142.3, 131.6, 129.2, 123.8, 123.3, 111.5 (d, J=20.5 Hz), 108.7, 99.9 (d, J=22.3 Hz), 80.7, 57.7, 38.8, 36.0, 26.0, 22.4, 22.3; MS (ES+) m/z 344.4 (M+1).
