反応 #561138

反応方程式

diisopropyl azodicarboxylate

Triphenylphosphine

5-bromo-2-nitrophenol

methyl(−)—(S)-lactate

→

(R)-methyl 2-(5-bromo-2-nitrophenoxy)propanoate

収率 94.0%

溶媒

methylene chloride

反応条件

後処理

1. 1
   温度The orange solution was warmed to room temperature
2. 2
   workup.STIRRINGstirred for 12 h
3. 3
   濃縮concentrated to ca. 1.0 mL
4. 4
   workup.ADDITIONdiluted with pentane (7 mL) and diethyl ether (8 mL)
5. 5
   ろ過filtered
6. 6
   洗浄rinsed with diethyl ether-pentane (15 mL)
7. 7
   濃縮The filtrate was concentrated to dryness under reduced pressure
8. 8
   その他the residue was purified by flash column chromatography on silica gel (hexanes to ethyl acetate gradient)

実験手順

Triphenylphosphine (624.0 mg, 2.38 mmol) was added at room temperature to a solution of 5-bromo-2-nitrophenol A-15 (400.0 mg, 1.83 mmol) and methyl(−)—(S)-lactate (0.149 mL, 1.56 mmol) in anhydrous methylene chloride (18.3 mL) under an atmosphere of argon. After 10 mins of stirring, the reaction mixture was cooled to 0° C. and diisopropyl azodicarboxylate (0.360 mL, 1.83 mmol) was added dropwise. The orange solution was warmed to room temperature, stirred for 12 h, then concentrated to ca. 1.0 mL, diluted with pentane (7 mL) and diethyl ether (8 mL), filtered and rinsed with diethyl ether-pentane (15 mL). The filtrate was concentrated to dryness under reduced pressure, and the residue was purified by flash column chromatography on silica gel (hexanes to ethyl acetate gradient) to give (R)-methyl 2-(5-bromo-2-nitrophenoxy)propanoate (R)-A-16 as a yellow solid (525.0 mg; Yield=94%). MS (ESI) [M+1]+ 304, 306.

出典