Potassium Carbonate → 2-[2-[[Tert-butyl(dimethyl)silyl]oxymethyl]-3-tert-butylsilyloxy-3-methylbutoxy]-4-methoxy-5-thiophen-2-ylbenzaldehyde

Participants

Reaction Conditions

Reaction Steps

Ex-64A: To a solution of 2-hydroxy-4-methoxy-5-thiophen-2-yl-benzaldehyde (10.0 g, 42.7 mmol) in N,N-dimethylformamide (100 mL) was added potassium carbonate (11.8 g, 85.4 mmol) and the resulting yellow slurry was heated to 80° C. Once at 80° C., methanesulfonic acid 3-(tert-butyl-dimethyl-silanyloxy)-2-(tert-butyl-dimethyl-silanyloxymethyl)-propyl ester (Ex-50A, 19.5 g, 46.9 mmol) was added dropwise and the reaction was stirred for an additional 24 h at 80° C. and cooled to room temperature. The mixture was diluted with water (500 mL) and extracted with ethyl acetate (3×150 mL). The combined organic layers was sequentially washed with a saturated sodium bicarbonate solution (1×150 mL), water (1×150 mL), and brine (1×150 mL), dried over sodium sulfate, and concentrated to a brown oil. Silica gel chromatography (100% ethyl acetate to 10% ethyl acetate/hexanes) gave 19.0 g (81%) of 2-[3-(tert-butyl-dimethyl-silanyloxy)-2-(tert-butyl-dimethyl-silanyloxymethyl)-propoxy]-4-methoxy-5-thiophen-2-yl-benzaldehyde as an off-white solid, mp 91–92° C. 1H-NMR (300 MHz, CDCl3) δ 10.37 (s, 1H), 8.12 (s, 1H), 7.44 (dd, 1H, J=3.6, 1.2 Hz), 7.29 (d, 1H, J=5.1 Hz), 7.07 (dd, 1H, J=5.1, 3.6 Hz), 6.54 (s, 1H), 4.19 (d, 2H, J=6.0 Hz), 3.99 (s, 3H), 3.72–3.82 (m, 4H), 2.28 (pentet, 1H, J=6.0 Hz), 0.88 (s, 18H), 0.048 (s, 12H). MS (EI) m/z=550 ([M]+, 100%). Anal. Calcd. for C28H46O5SSi2: C, 61.05; H, 8.42; S, 5.82. Found: C, 61.20; H, 8.74; S, 5.69.

Provenance & Evidence