tert-butyl N-[(2S)-3-(cyclopenten-1-yl)-1-[methoxy(methyl)amino]-1-oxopropan-2-yl]carbamate → tert-Butyl (S)-(1-(cyclopent-1-en-1-yl)-4-methyl-3-oxopent-4-en-2-yl)carbamate

HRID 58846Notes

Reaction equation

[C:1]1([CH2:6][C@H:7]([NH:14][C:15](=[O:21])[O:16][C:17]([CH3:20])([CH3:19])[CH3:18])[C:8](N(OC)C)=[O:9])[CH2:5][CH2:4][CH2:3][CH:2]=1.[CH2:22]=[C:23]([Mg]Br)[CH3:24]>C1COCC1>[C:1]1([CH2:6][C@H:7]([NH:14][C:15](=[O:21])[O:16][C:17]([CH3:18])([CH3:19])[CH3:20])[C:8](=[O:9])[C:23]([CH3:24])=[CH2:22])[CH2:5][CH2:4][CH2:3][CH:2]=1

Participants

Conditions

Temperature: 0 °C

Procedure

To a solution of (S)-tert-butyl (3-(cyclopent-1-en-1-yl)-1-(methoxy(methyl)amino)-1-oxopropan-2-yl)carbamate (81 g, 0.27 mol) in THF (600 mL) was added freshly prepared prop-1-en-2-ylmagnesium bromide (96.0 mL, 1.08 mol) at 0° C. dropwise. After completion of the addition, the reaction mixture was stirred at 0° C. for 2 h then quenched with saturated aqueous ammonium chloride (500 mL). The resulting mixture was extracted with EtOAc (400 mL×2). The organic phases were combined, dried over anhydrous sodium sulfate, and concentrated. The residue was purified by flash column chromatography on silica gel (petroleum ether/EtOAc=100:1) to afford (S)-tert-butyl (1-(cyclopent-1-en-1-yl)-4-methyl-3-oxopent-4-en-2-yl)carbamate as colorless oil (39.3 g, 52% yield).

Workup

additionAfter completion of the addition
customthen quenched with saturated aqueous ammonium chloride (500 mL)
extractionThe resulting mixture was extracted with EtOAc (400 mL×2)
dry with materialdried over anhydrous sodium sulfate
concentrationconcentrated
customThe residue was purified by flash column chromatography on silica gel (petroleum ether/EtOAc=100:1)

Sources & evidence

ORD record: ord-04ec453a25ad4ecdbabdc859f1f41889
Source dataset: uspto-grants-2016_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09434761B2

Reaction notes

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