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

HRID 658135Notes

Reaction equation

HRID 658135 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). An argon protective gas atmosphere is passed through with a needle (˜10 min). The solution is placed in an ultrasonic 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 a pressure of 3.5 bar of hydrogen 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 with a needle (˜10 min)
  2. customThe solution is placed in an ultrasonic 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-5ca2b8bf44c74e57951d92116b9508cd
Source dataset
uspto-grants-2011_12
Patent number
US08076285B2

Reaction notes

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