Reaktion #1340592

Reaktionsgleichung

Weinreb amide

(S)-2-(((Benzyloxy)carbonyl)amino)-3-(4-(((tert-butoxycarbonyl)amino)methyl)phenyl)-N-methoxy-N-methylpropionamide

EtOAc

2-Bromopropene

tBuLi

→

title compound

(S)-Benzyl (1-(4-((tert-butyloxycarbonylamino)methyl)phenyl)-4-methyl-3-oxopent-4-en-2-yl)carbamate

Lösungsmittel

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added slowly
2. 2
   Sonstigeconsumption of the Weinreb amide
3. 3
   workup.ADDITIONA saturated aqueous NH4Cl solution and EtOAc were added
4. 4
   Sonstigethe layers were separated
5. 5
   ExtraktionThe organic layer was extracted with brine
6. 6
   Trocknendried over MgSO4
7. 7
   Einengenconcentrated under reduced pressure

Vorschrift

2-Bromopropene (3.5 eq., 14.0 mmol, 1.25 mL) was dissolved in THF (50 mL) and cooled to −78° C. tBuLi (6.5 eq., 26.0 mmol, 16.3 mL; 1.6 M in hexane) was added slowly and the mixture was stirred for 1 hour at −78° C. after which Weinreb amide 11 (1 eq., 4.0 mmol, 1.89 g) was added in THF (5 mL). The mixture was allowed to warm to −20° C. in 6 hours after which TLC analysis indicated complete consumption of the Weinreb amide. A saturated aqueous NH4Cl solution and EtOAc were added and the layers were separated. The organic layer was extracted with brine, dried over MgSO4 and concentrated under reduced pressure. The title compound was obtained after column chromatography (20%→50% EtOAc/PE) as a colourless oil (yield: 1.71 g, 3.77 mmol, 94%). 1H NMR (400 MHz, CDCl3): δ=7.33-7.24 (m, 5H), 7.11 (d, J=7.87 Hz, 2H), 6.97 (d, J=8.00 Hz, 2H), 6.03 (s, 1H), 5.85 (s, 1H), 5.77 (d, J=8.18 Hz, 1H), 5.30 (dd, J=14.10, 6.11 Hz, 1H), 5.12-5.08 (m, 1H), 5.04 (dd, J=26.54, 12.35 Hz, 2H), 4.21 (d, J=5.41 Hz, 2H), 3.09 (dd, J=13.79, 5.88 Hz, 1H), 2.89 (dd, J=13.76, 5.97 Hz, 1H), 1.84 (s, 3H), 1.44 (s, 9H) ppm. 13C NMR (100 MHz, CDCl3): δ=199.28, 155.66, 155.34, 141.99, 137.40, 136.13, 134.60, 129.27, 128.17, 127.80, 127.71, 126.50, 79.01, 66.45, 55.13, 43.96, 38.76, 28.14, 17.44 ppm. HRMS: calcd. for C26H32N2O5 453.23840 [M+H]+. Found 453.23818.

Quelle