Reaction Steps
Following the procedure as described in EXAMPLE 8 and making non-critical variations using 7′-chloro-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′-chloro-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 (98%) as a colorless solid: mp 192-193° C. (hexanes/ethyl acetate); 1H NMR (300 MHz, DMSO-d6) δ 7.23-7.18 (m, 1H), 7.08-6.98 (m, 2H), 6.53 (d, J=17.6 Hz, 1H), 6.42 (d, J=2.0 Hz, 1H), 4.80-4.69 (m, 2H), 4.53-4.47 (m, 2H), 4.20-4.11 (m, 1H), 3.95-3.60 (m, 4H), 2.99-2.93 (m, 2H), 2.04-1.59 (m, 4H); 13C NMR (75 MHz, DMSO-d6) δ177.7, 177.6, 161.1 (2C), 160.5, 160.3, 138.3, 138.0, 135.8, 135.4, 130.7, 130.6, 124.1, 122.7, 122.6, 120.5, 120.2, 119.9, 119.8, 119.2, 118.8, 114.3, 114.2, 92.4, 92.2, 80.0, 76.3, 76.1, 72.0, 72.0, 67.2, 66.9, 56.7, 56.5, 45.0, 44.9, 28.3, 28.2, 24.9, 24.9; MS (ES+) m/z 397.7 (M+1), 399.7 (M+1).
