反应详情

温度

-78 °C

A solution of the above ethyl ester 3 (1.0 g, 5.9 mmol) was dissolved in hexanes (50 mL) and cooled to −78° C. A solution of DIBAL (5.8 mL 1.0 M in cyclohexane) was added dropwise. After 15 m, diethyl ether (50 mL) was added and the mixture was stirred with Rochelle's salt solution (25 mL) for 10 m. The organic layer was separated, dried and filtered. Chromatography on SiO2 with 7% Et2O:Hx delivered the aldehyde as a clear colorless oil, 0.52 g (74%). The aldehyde 4 was subjected to the Büchi protocol as described above. The fumarate salt of the imidazole 5 (U-1) was obtained in three steps (25% overall).

1. customThe organic layer was separated
2. customdried
3. filtrationfiltered