Reaction Steps
Following the procedure as described in EXAMPLE 8 and making non-critical variations using (R)-2,3-dihydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indol]-2′(1′H)-one to replace spiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-2′(1′H)-one, and (S)-2-(iodomethyl)-1,4-dioxane (Kim, H. Y. et al., Bioorg. Med. Chem. Lett. (2005), 15:3207-11) to replace (R)-(1,4-dioxan-2-yl)methyl 4-methylbenzenesulfonate, (8R)-1′-[(2R)-1,4-dioxan-2-ylmethyl]-2,3-dihydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indol]-2′(1′H)-one was obtained (51%) as a colorless solid: mp 198-199° C. (diethyl ether/hexanes); 1H NMR (300 MHz, CDCl3) δ7.30 (ddd, J=7.8, 7.8, 1.1 Hz, 1H), 7.16 (d, J=7.8 Hz, 1H), 7.08-7.02 (m, 2H), 6.49 (s, 1H), 6.24 (s, 1H), 4.88 (d, J=9.0 Hz, 1H), 4.64 (d, J=9.0 Hz, 1H), 4.22-4.16 (m, 2H), 4.13-4.08 (m, 2H), 3.98-3.78 (m, 4H), 3.75-3.56 (m, 4H), 3.47-3.38 (m, 1H); 13C NMR (75 MHz, CDCl3) δ177.9, 155.3, 144.7, 142.7, 138.4, 132.4, 128.9, 123.8, 123.5, 121.3, 111.7, 109.6, 99.5, 80.1, 73.3, 69.2, 66.7, 66.5, 64.6, 64.0, 58.1, 41.8; MS (ES+) m/z 396.0 (M+1).
