Reaction Steps
Following the procedure as described in EXAMPLE 8 and making non-critical variations using 7′-fluoro-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-2′(1′H)-one to replace spiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-2′(1′H)-one, and (R)-(tetrahydrofuran-2-yl)methyl 4-methylbenzenesulfonate to replace (R)-(1,4-dioxan-2-yl)methyl 4-methylbenzenesulfonate, 7′-fluoro-1′-[(2R)-tetrahydrofuran-2-ylmethyl]-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-2′(1′H)-one was obtained (28%) as a colorless solid: mp 169-170° C. (diethyl ether); 1H NMR (300 MHz, DMSO-d6) δ7.35-7.32 (m, 1H), 7.15-7.01 (m, 2H), 6.56 (d, J=28.1 Hz, 1H), 6.41 (d, J=2.9 Hz, 1H), 4.78-4.67 (m, 2H), 4.52-4.46 (m, 2H), 4.30-3.93 (m, 3H), 3.82-3.93 (m, 2H), 2.99-2.91 (m, 2H), 2.06-1.58 (m, 4H); 13C NMR (75 MHz, DMSO-d6) δ176.7, 156.8, 156.7, 154.3, 142.9, 142.7, 136.1, 136.0, 132.8, 131.5, 131.3, 128.7 (2C), 123.3 (2C), 122.7, 121.9, 121.8, 109.7, 109.6, 109.5, 104.5, 104.4, 92.4, 79.5, 75.6, 75.4, 67.1, 67.0, 57.2, 43.8, 43.7, 28.5, 28.4, 28.1, 25.0, 24.9.
