Diisobutylaluminumhydride → HCID 89872641, compound

Participants

Reaction Conditions

Reaction Steps

A solution of 5-(benzyloxy)-7-methoxy-2,2-dimethyl-4H-benzo[d][1,3]dioxin-4-one (Example 1B, 6.76 g, 21.5 mmol) in dichloromethane (120 mL) was cooled to −78° C. and treated with 43 mL (64.5 mmol) of a 1.5 M solution of diisobutylaluminum hydride in toluene added dropwise over 20 min. The resulting mixture was then stirred at −78° C. for 3 h. The reaction mixture was quenched by the careful addition of methanol (5 mL) added dropwise over 15 min, followed by 1N hydrochloric acid (50 mL) added dropwise over 15 min. The cooling bath was then removed and an additional 150 mL of 1N hydrochloric acid was added over 20 min. The mixture was then stirred at 22° C. for 2 h and diluted with dichloromethane (400 mL). The organic phase was collected and the aqueous phase (pH ˜1) was extracted with dichloromethane (3×50 mL). The combined organic extracts were washed with brine, dried over anhydrous magnesium sulfate and concentrated in vacuo. The residual oil was diluted with tetrahydrofuran (70 mL), treated with 10 mL of 0.1N hydrochloric acid and stirred at 20° C. for 2 h. The reaction mixture was diluted with ethyl acetate (300 mL), washed with brine, dried over anhydrous magnesium sulfate, evaporated in vacuo to give a clear oil. Chromatography on silica gel (4×13 cm, elution toluene) gave 4.08 g (73% yield) of the title aldehyde as a clear oil which solidified on standing. LC (Method C): 2.237 min. HRMS (ESI) calcd for C15H15O4 [M+H]+ m/z 259.0965, found 259.1153. 1H NMR (CDCl3, 600 MHz) δ 3.80 (s, 3H), 5.07 (s, 2H), 5.97 (d, J=2.1 Hz, 1H), 6.01 (d, J=2.1 Hz, 1H), 7.3-7.4 (m, 5H), 10.15 (s, 1H), 12.49 (s, 1H).

Provenance & Evidence