반응 #87487

반응 방정식

aluminum

tetrahydrofuran

(2R,3S,4S)-2,3,4-tris-benzyloxy-5-hydroxy-6-(4-methoxy-benzyloxy)-5-(4-methoxy-benzyloxymethyl)-hexanoic acid methoxy-methyl-amide

tetrahydrofuran

n-Butyl lithium

oxygen

4-bromo-1-chloro-2-(4-ethoxy-benzyl)-benzene

→

3,4,5-tris-benzyloxy-2-[4-chloro-3-(4-ethoxy-benzyl)-phenyl]-6,6-bis-(4-methoxy-benzyloxymethyl)-tetrahydro-pyran-2-ol

수율 38.0%

용매

Diethyl ether

반응 조건

후처리

1. 1
   기타dried Biotage™ microwave vial 10-20 mL
2. 2
   기타sealed with its
3. 3
   기타cap
4. 4
   기타at −78° C.
5. 5
   workup.STIRRINGthe resulting mixture was stirred at −78° C. for 1 hour
6. 6
   온도to maintain cold temperature
7. 7
   기타the reaction was quenched by dropwise addition of aqueous 1M hydrochloric acid solution
8. 8
   workup.STIRRINGThe resulting biphasic mixture was stirred at room temperature for 15 minutes
9. 9
   기타The organic phase was separated
10. 10
    세척washed with brine
11. 11
    건조dried over magnesium sulfate
12. 12
    여과filtered
13. 13
    농축concentrated
14. 14
    기타Chromatography over silica gel using a gradient of 10 to 40% ethyl acetate in heptane gave the product
15. 15
    workup.ADDITIONas a mixture of isomers (280 mg, 38% yield)

실험 절차

n-Butyl lithium (1.0 mL, 2.5 M/hexanes, 3.25 equivalents) was added dropwise (1 drop every 5 seconds) to an oxygen degassed solution (placed in a pre dried Biotage™ microwave vial 10-20 mL sealed with its cap and placed under a positive stream of nitrogen gas) of 4-bromo-1-chloro-2-(4-ethoxy-benzyl)-benzene (815 mg, 3.25 equivalents) in anhydrous tetrahydrofuran (2.9 mL) at −78° C. and the resulting solution was stirred at this temperature for an additional hour. A solution of (2R,3S,4S)-2,3,4-tris-benzyloxy-5-hydroxy-6-(4-methoxy-benzyloxy)-5-(4-methoxy-benzyloxymethyl)-hexanoic acid methoxy-methyl-amide (l-1q) (600 mg) in anhydrous tetrahydrofuran (1.45 mL) was then added dropwise over 1.3 hours using a syringe pump and the resulting mixture was stirred at −78° C. for 1 hour before being allowed to warm to −25° C. over 14 hours (put in a deep Dewar covered with aluminum foil to maintain cold temperature; size of Dewar: external diameter 10 cm, internal diameter 8 cm, height 9 cm). Diethyl ether was added and the reaction was quenched by dropwise addition of aqueous 1M hydrochloric acid solution. The resulting biphasic mixture was stirred at room temperature for 15 minutes. The organic phase was separated, washed with brine, dried over magnesium sulfate, filtered and concentrated. Chromatography over silica gel using a gradient of 10 to 40% ethyl acetate in heptane gave the product as a mixture of isomers (280 mg, 38% yield). HRMS calculated for C59H61O10ClNa (M+Na+) 987.3845. found 987.3840.

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