1,4-Dioxane → N-tert-Butoxycarbonyl-3-tert-butyl-D-alanine methyl ester

HRID 2237367Notes

Reaction equation

HRID 2237367 reaction equation
[C:1]([O:5][C:6]([NH:8]/[C:9](=[CH:14]\[C:15]([CH3:18])([CH3:17])[CH3:16])/[C:10]([O:12][CH3:13])=[O:11])=[O:7])([CH3:4])([CH3:3])[CH3:2].O1CCOCC1.[H][H]>C(O)C>[CH3:13][O:12][C:10](=[O:11])[C@@H:9]([CH2:14][C:15]([CH3:18])([CH3:17])[CH3:16])[NH:8][C:6]([O:5][C:1]([CH3:2])([CH3:3])[CH3:4])=[O:7]

Participants

5

Reactant 3

HCID 312751,4-DioxaneHCID 59302433Methyl (Z)-2-[(tert-butoxycarbonyl)amino]-4,4-dimethylpent-2-enoateHCID 178418361HCID 178418361, compound

Product 1

HCID 59302429N-tert-Butoxycarbonyl-3-tert-butyl-D-alanine methyl ester

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

Methyl (2Z)-2-[(tert-butoxycarbonyl)amino]-4,4-dimethylpent-2-enoate (Example 4A, 60 g, 233.2 mmol) is dissolved in ethanol p.a./dioxane 3:1 (1000 ml). Argon is passed through for about 10 min using a cannula. The solution is placed into an ultrasound bath (about 5 min), and (+)-1,2-bis[(2R,5R)diethylphospholano]benzene(cyclooctadiene)rhodium(I) triflate (600 mg, 1% by weight) is added. The mixture is hydrogenated under 3.5 bar hydrogen pressure and at RT for 3 days. The reaction mixture is filtered through kieselguhr and the eluate is concentrated. The crude product is chromatographed (silica gel, eluent: cyclohexane/ethyl acetate 4:1). 60 g (99% of theory) of the title compound are obtained.

Workup

  1. customis passed through for about 10 min
  2. customThe solution is placed into an ultrasound bath
  3. filtrationThe reaction mixture is filtered through kieselguhr
  4. concentrationthe eluate is concentrated
  5. customThe crude product is chromatographed (silica gel, eluent: cyclohexane/ethyl acetate 4:1)

Sources & evidence

ORD record
ord-ac60d7ad70144731aed4b46461b99a54
Source dataset
uspto-grants-2010_05
Patent number
US07718611B2

Reaction notes

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