(S)-tert-butyl 1-(tert-butyldimethylsilyloxy)but-3-en-2-yl(2-(methoxy(methyl)amino)-2-oxoethyl)carbamate → (S)-tert-butyl 1-(tert-butyldimethylsilyloxy)but-3-en-2-yl(2-oxopent-3-enyl)carbamate

Participants

Reaction Conditions

Reaction Steps

To a solution of (S)-tert-butyl 1-(tert-butyldimethylsilyloxy)but-3-en-2-yl(2-(methoxy(methyl)amino)-2-oxoethyl)carbamate (Intermediate 5, 32.5 g, 80.73 mmol) in THF (400 mL) under nitrogen at 0° C. was added prop-1-enylmagnesium bromide (323 ml, 161.45 mmol) dropwise. The reaction mixture was stirred at 0° C. for 1 hour, then quenched with 400 mL 10% citric acid, diluted further with 100 mL water and extracted with ether. The organics were concentrated and the resulting oil was dissolved in ether and washed with water and brine. The organics were dried over magnesium sulfate, filtered and concentrated. Silica gel chromatography (5%-20% ethyl acetate/hexanes) afforded the desired product as a colorless oil (27 g, 87%).

Provenance & Evidence