反应详情

A solution of (1,4-dioxa-spiro[4.5]dec-8-ylidene)-acetic acid methyl ester (5.50 g, 25.9 mmol) in 14 mL of dry THF was treated by nitromethane (2.10 mL, 38.9 mmol) followed by a 1M solution of tetrabutylammonium fluoride in THF (26.5 mL, 26.5 mmol). The resulting mixture was stirred at reflux for 20 h under nitrogen. After cooling, the mixture was diluted with water and extracted with three portions of ether. The etheral portions were combined, washed with a 10% aqueous solution of potassium hydrogensulfate, dried over anhydrous Na2SO4 and concentrated. The crude was purified by silica gel column chromatography using a 20% EtOAc:hexanes mixture as eluent to afford (8-Nitromethyl-1,4-dioxa-spiro[4.5]dec-8-yl)-acetic acid methyl ester (5.34 g, 75%) as a colorless oil.

1. temperatureat reflux for 20 h under nitrogen
2. temperatureAfter cooling
3. extractionextracted with three portions of ether
4. washwashed with a 10% aqueous solution of potassium hydrogensulfate
5. dry with materialdried over anhydrous Na2SO4
6. concentrationconcentrated
7. customThe crude was purified by silica gel column chromatography