tert-butyl (1S)-1-formyl-2-methylpropyl(methyl)carbamate → Ethyl (2E,4S)-N-Boc-N-methyl-4-amino-2.5-dimethylhex-2-enoate

HRID 2105119Notes

Reaction equation

HRID 2105119 reaction equation
[C:1]([N:8]([CH3:15])[C@H:9]([CH:13]=O)[CH:10]([CH3:12])[CH3:11])([O:3][C:4]([CH3:7])([CH3:6])[CH3:5])=[O:2].[C:16]([CH2:21][CH:22]=P(C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)([O:18][CH2:19][CH3:20])=[O:17]>C(Cl)Cl.O>[C:1]([N:8]([CH3:15])[C@@H:9]([CH:10]([CH3:12])[CH3:11])/[CH:13]=[C:21](\[CH3:22])/[C:16]([O:18][CH2:19][CH3:20])=[O:17])([O:3][C:4]([CH3:7])([CH3:6])[CH3:5])=[O:2]

Participants

5

Reactant 2

HCID 10353241tert-butyl (1S)-1-formyl-2-methylpropyl(methyl)carbamateHCID 12607919Ethyl 3-(triphenyl-lambda~5~-phosphanylidene)propanoate

Product 1

HCID 15342220Ethyl (2E,4S)-N-Boc-N-methyl-4-amino-2.5-dimethylhex-2-enoateYield 82%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6344DichloromethaneSolvent

Procedure

To a solution of aldehyde 13 (1.75 g, 8.7 mmol) in dry CH2Cl2 (9.0 mL) under an argon atmosphere at room temperature was added (carbethoxyethylidene)triphenylphosphorane (4.19 g, 11.3 mmol) and stirring was continued for a 4 h. The reaction mixture was diluted with water (100 mL) and extracted with diethyl ether (3×100 mL). The combined organic extracts were washed with saturated aqueous sodium chloride (100 mL), dried with magnesium sulfate and concentrated in vacuo. The crude oil was purified by flash chromatography (silica gel, 2:23 diethyl ether-pet. ether) to afford the required E-2-alkenoate 14 as a colourless oil (2.13 g, 82% yield). 1H-NMR (200 MHz, CDCl3) 0.74 (d, J=6 Hz, 3H, CH3), 0.79 (d, J=6 Hz, 3H, CH3), 1.17 (t, J=0.7 Hz, 3H, CH3), 1.34 (s, 9H, Boc-(CH3)3), 1.72 (m, 1H, CH), 1.78 (s, 3H, —CH3), 2.60 (bs, 3H, NCH3), 4.08 (q, J=7 Hz, 2H, CH2), 4.15-4.20 (m, 0.5H, CH), 4.21-4.32 (m, 0.5H, CH), 6.54 (d, J=8 Hz, 1H, CH); Exact mass calc'd for C16H30N04 (M+H)+: 300.21750; Found (DCI): 300.21754. Optical rotation obtained was [α]D25 +61.1 (c 9.1, CHCl3).

Workup

  1. extractionextracted with diethyl ether (3×100 mL)
  2. washThe combined organic extracts were washed with saturated aqueous sodium chloride (100 mL)
  3. dry with materialdried with magnesium sulfate
  4. concentrationconcentrated in vacuo
  5. customThe crude oil was purified by flash chromatography (silica gel, 2:23 diethyl ether-pet. ether)

Sources & evidence

ORD record
ord-469c4f9753b244928057add3e47bdca9
Source dataset
uspto-grants-2009_08
Patent number
US07579323B1

Reaction notes

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