反应详情

温度

-60 °C

tert-butyl 6-azaspiro[2.5]octane-6-carboxylate (Intermediate 2, 1 g, 4.73 mmol) dissolved in 20 ml of Et2O was cooled to −60° C., then N,N,N′,N′-tetramethyl ethylendiamine (0.71 ml, 4.73 mmol) and secBuLi 1.4M in hexane (4.05 ml, 5.68 mmol) were added. After 10 minutes at −60° C., the temperature was raised to −20° C. for 30 minutes, then the reaction was cooled to −78° C. and dimethylformamide (0.55 ml, 7.09 mmol, dissolved in 5 ml of Et2O) was added. After 30 minutes a saturated aqueous solution of NH4Cl (8 ml) was slowly added, then reaction was allowed to reach room temperature. Reaction was extracted with Et2O (3×50 ml), the organic solvent was dried (Na2SO4) and evaporated to obtain a crude that was purified by silica gel chromatography (petroleum ether/ethylacetate from 95/5 to 85/15). (±) tert-butyl 5-formyl-6-azaspiro[2.5]octane-6-carboxylate was obtained as light yellow solid (400 mg).

1. temperaturethe temperature was raised to −20° C. for 30 minutes
2. temperaturethe reaction was cooled to −78° C.
3. customreaction
4. customto reach room temperature
5. customReaction
6. extractionwas extracted with Et2O (3×50 ml)
7. dry with materialthe organic solvent was dried (Na2SO4)
8. customevaporated
9. customto obtain a crude that
10. customwas purified by silica gel chromatography (petroleum ether/ethylacetate from 95/5 to 85/15)