Reaction Steps
Sodium hydride (2.54 g., 0.106 mol, 2.5 equiv.; 80% dispersion, unwashed) is suspended in 75 mL of DMSO. A solution of 2,3-dihydroxybenzaldehyde (5.84 g., 42.3 mmol, 1 equiv.) in 30 mL of DMSO is added dropwise with water bath cooling, and the mixture allowed to stir 1 hr. at room temperature. A solution of 2-chloromethyl-5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalene (18a) (10 g., 42.3 mmol, 1 equiv.) is added and the mixture is allowed to stir overnight at room temperature. The mixture is then poured into half-saturated ammonium chloride solution, and extracted with EtOAc. The aqueous phase is saturated with sodium chloride, and then extracted twice with EtOAc. The combined organic phase is washed with brine, dried (MgSO4), and evaporated. Chromatography on silica gel using 50% CH2Cl2 /hexane affords 3-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-2-naphthalenyl)methoxy-salicylaldehyde (19a) as a yellow oil (6.02 g., 17.8 mmol, 44%) which occasionally crystallizes upon standing: UVmax (CHCl3) 268 nm (ε=9894), 240 nm (ε=6181), 350 nm (ε=2513); 1H NMR (300 MHz, CDCl3) δ 11.01 (s, 1H, OH), 9.91 (s, 1H, CHO), 7.33 (d, J=2 Hz, 1H, ArH), 7.29 (d, J=8 Hz, 1H, ArH), 7.21-7.13 (m, 3H, ArH), 6.90 (dd, J=8, 8 Hz, 1H, ArH), 5.10 (s, 2H, ArCH2O), 1.66 (s, 4H, CH2CH2), 1.25 (s, 12H, 4×CH3); 13C NMR (75 MHz, CDCl3) δ 196.45 (C=O), 152.31, 147.46, 145.07, 144.86, 133.33, 126.93, 125.90, 125.12, 125.01, 121.06, 120.97, 119.46, 71.78, 35.03, 35.00, 34.26, 34.16, 31.83; IR (film) 2960, 2926, 2860, 1658, 1456, 1388, 1364, 1276, 1252, 1216, 750, 736 cm-1 ; MS (DCI) m/e 339 (MH+), 201 (C15H21+). Anal. Calcd for C22H26O3.0.4 H2O: C, 76.45; H, 7.81. Found: C, 76.62; H, 7.62.
