[OH:1][C:2]1[CH:11]=[C:10]2[C:5]([C:6](=[O:12])[CH2:7][CH2:8][O:9]2)=[CH:4][CH:3]=1.N1C=CN=C1.[CH:18]([Si:21](Cl)([CH:25]([CH3:27])[CH3:26])[CH:22]([CH3:24])[CH3:23])([CH3:20])[CH3:19].O>CN(C=O)C>[CH:18]([Si:21]([CH:25]([CH3:27])[CH3:26])([CH:22]([CH3:24])[CH3:23])[O:1][C:2]1[CH:11]=[C:10]2[C:5]([C:6](=[O:12])[CH2:7][CH2:8][O:9]2)=[CH:4][CH:3]=1)([CH3:20])[CH3:19]7-Hydroxy-4-chromanone (1.2 g, 7.3 mmol; Dann et al., Ann. 587, 16, 1954) and imidazole (1.0 g, 14.7 mmol) were dissolved in DMF (10 ml). Triisopropylsilyl chloride (1.8 ml, 8.2 mmol) in DMF (2 ml) was added dropwise at ambient temperature over 10 minutes. After stirring for 3 hours, the mixture was poured onto 100 ml ice and water, and extracted with ether (2×100 ml). The combined ether extracts were washed with 1M LiCl and then brine, dried over CaSO4, and concentrated to a brown oil which was purified by Kugelrohr distillation (0.5 torr, 70°-90° C). This removed a colorless, viscous oil impurity and left the brown oil product in the distillation pot (2.0 g, 85%). IR (KBr) 2945, 2867, 1685, 1605, 1268, 1163. HRMS Calcd. for MH+, 320.1807; observed, 320.1842.
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