反応 #168353

反応方程式

octahydrocyclopenta[b][1,4]oxazine hydrochloride

benzyl chloroformate

Triethylamine

→

benzyl hexahydrocyclopenta[b][1,4]oxazine-4(4aH)-carboxylate

溶媒

dichloromethane

反応条件

後処理

1. 1
   その他The mixture was quenched with saturated aqueous sodium bicarbonate
2. 2
   抽出extracted with dichloromethane (2×)
3. 3
   乾燥The combined organic layers were dried over sodium sulfate
4. 4
   ろ過filtered
5. 5
   濃縮concentrated under reduced pressure
6. 6
   その他The residue was purified by silica gel chromatography (0-100% ethyl acetate/hexanes, linear gradient)
7. 7
   その他purified by chiral supercritical fluid chromatography (Chiralpak AZ-H, 21×250 mm, 10% methanol in CO2)

実験手順

To octahydrocyclopenta[b][1,4]oxazine hydrochloride (purchased from Enamine) (300 mg, 1.83 mmol) dissolved in dichloromethane (2.4 mL) was added benzyl chloroformate (0.44 mL, 2.57 mmol). Triethylamine (0.72 mL, 5.13 mmol) was added slowly to the reaction mixture, and the reaction was stirred for 16 hours at room temperature. The mixture was quenched with saturated aqueous sodium bicarbonate and extracted with dichloromethane (2×). The combined organic layers were dried over sodium sulfate, filtered, and concentrated under reduced pressure. The residue was purified by silica gel chromatography (0-100% ethyl acetate/hexanes, linear gradient), and then purified by chiral supercritical fluid chromatography (Chiralpak AZ-H, 21×250 mm, 10% methanol in CO2) to afford the trans stereoisomers of benzyl hexahydrocyclopenta[b][1,4]oxazine-4(4aH)-carboxylate. (4aS,7aS)-Benzyl hexahydrocyclopenta[b][1,4]oxazine-4(4aH)-carboxylate (faster eluting enantiomer): MS ESI calc'd. for C15H19NO3 [M+H]+ 262. found 262; (4aR,7aR)-Benzyl hexahydrocyclopenta[b][1,4]oxazine-4(4aH)-carboxylate (slower eluting enantiomer): MS ESI calc'd. for C15H19NO3 [M+H]+ 262. found 262.

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