Reaction Steps
A solution of n-butyllithium (20.0 mL, 1.6 M, 32.2 mmol) in hexanes was added dropwise to a cooled (0° C.) solution of indene (5.35 g, 32.2 mmol) in 50 mL of diethyl ether. The reaction solution turned yellow and was warmed to 25° C. for 30 minutes. This yellow solution was added dropwise to a cooled (0° C.) solution of bromoacetaldehyde diethylacetal (5.00 mL, 32.2 mmol) in 50 mL of diethyl ether. The reaction mixture turned bright red after warming to 25° C. and was stirred for 12 hours, during which time it darkened to brown. The solvent was then removed in vacuo leaving brown oil. Methylene chloride (100 mL) was added to give a cloudy white mixture which was extracted with deionized water (3×100 mL). The brown organic layer was dried over Na2SO4 and then solids were separated by filtration. Solvent was removed from the filtrate in vacuo resulting in brown oil. Yield: 5.48 g, 23.5 mmol (85%). 1H NMR (CDCl3, 600 MHz): δ 7.43 (d, 3JHH=7.2 Hz, 1H, H4), 7.35 (d, 3JHH=7.8 Hz, 1H, H7), 7.25 (t, 3JHH=7.2 Hz, 1H, H5), 7.19 (t, 3JHH=7.2 Hz, 1H, H6), 6.80 (dd, 1H, H2), 6.61 (dd, 1H, H3), 4.68 (m, 1H, CH), 3.69 (dm, 2H, OCH2CH3), 3.56 (m, 1H, H1), 3.52 (dm, 2H, OCH2CH3), 2.22 (m, 1H, CH2), 1.71 (m, 1H, CH2), 1.24 (t, 3JHH=7.2 Hz, 3H, OCH2CH3), 1.19 (t, 3JHH=7.2 Hz, 3H, OCH2CH3). 13C{1H} NMR (CDCl3, 150.8 MHz): 147.51 (s, C7a), 144.13 (s, C3a), 139.13 (s, C3), 130.79 (s, C2), 126.56 (s, C5), 124.73 (s, C6), 123.00 (s, C4), 121.05 (s, C7), 102.10 (s, CH), 61.44 (s, OCH2CH3), 61.23 (s, OCH2CH3), 46.66 (s, C1), 35.51 (s, CH2), 15.38 (s, OCH2CH3). MS (ES) m/z (assignment, relative intensity): 255.2 (C15H20O2Na, [M+Na]+, 100%). Anal. Calcd. for C15H20O2: C, 77.54; H, 8.68. Found: C, 77.34; H, 8.76.
