CN(C)CCNC.C([Li])CCC.[CH3:13][O:14][C:15]1[C:24]2[C:19](=[CH:20][CH:21]=[CH:22][CH:23]=2)[CH:18]=[CH:17][C:16]=1[CH:25]=[O:26].[C:27](=[O:29])=[O:28].Cl>O1CCCC1>[OH:26][CH:25]1[O:29][C:27](=[O:28])[C:17]2[CH:18]=[C:19]3[C:24](=[C:15]([O:14][CH3:13])[C:16]1=2)[CH:23]=[CH:22][CH:21]=[CH:20]3N,N,N′-Trimethylethylene diamine (0.82 ml, 6.3 mmol) was dissolved in tetrahydrofuran (16 ml) and cooled to −20° C. n-Butyl lithium (1.6M in hexanes, 3.9 ml, 6.24 mmol) was added and the reaction stirred at −20° C. for 15 min. 1-Methoxy-2-naphthaldehyde (0.96 g, 5.9 mmol) was added followed by n-butyl lithium (1.6M in hexanes, 11.25 ml, 18 mmol) and the reaction stirred at 25° C. for 3 h. Solid carbon dioxide was added and the reaction left until the excess carbon dioxide had sublimed. Stirring continued for 15 min before addition of hydrochloric acid (2N, 50 ml). The mixture was extracted with dichloromethane (50 ml, ×3). The combined extracts were dried (MgSO4) and the solvent evaporated under vacuum. The oily residue was preabsorbed onto silica and purified by SPE (silica, 10 g) eluting with an ethyl acetate/cyclohexane gradient to give 3-hydroxy-4-methoxynaphtho[2,3-c]furan-1(3H)-one (50 mg, 3.7%).
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