반응 #561138

반응 방정식

diisopropyl azodicarboxylate

Triphenylphosphine

5-bromo-2-nitrophenol

methyl(−)—(S)-lactate

→

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

수율 94.0%

용매

methylene chloride

반응 조건

후처리

1. 1
   온도The orange solution was warmed to room temperature
2. 2
   workup.STIRRINGstirred for 12 h
3. 3
   농축concentrated to ca. 1.0 mL
4. 4
   workup.ADDITIONdiluted with pentane (7 mL) and diethyl ether (8 mL)
5. 5
   여과filtered
6. 6
   세척rinsed with diethyl ether-pentane (15 mL)
7. 7
   농축The filtrate was concentrated to dryness under reduced pressure
8. 8
   기타the residue was purified by flash column chromatography on silica gel (hexanes to ethyl acetate gradient)

실험 절차

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.

출처