(S)-2-(Boc-amino)-3-cyclohexyl-N-methoxy-N-methylpropanamide → (S)-tert-butyl (1-cyclohexyl-4-methyl-3-oxopent-4-en-2-yl)carbamate

Participants

Reaction Conditions

Reaction Steps

To (S)-tert-butyl (3-cyclohexyl-1-(methoxy(methyl)amino)-1-oxopropan-2-yl)carbamate (12.2 g, 38.9 mmol) in THF (150 mL) at 0° C. was added isopropenylmagnesium bromide (71.2 mL of a 1.5 N solution in methyl-THF, 0.107 mol) dropwise. After stirring at 0° C. for 2 h the mixture was quenched with heptane/citric acid (1:1). The product was extracted with EtOAc (2×), washed with brine, dried with sodium sulfate, filtered, and concentrated. The crude product was triturated from cold (0° C.) methanol to provide (S)-tert-butyl (1-cyclohexyl-4-methyl-3-oxopent-4-en-2-yl)carbamate (5.36 g, 49%) as a colorless crystalline solid. MS (EI) for C17H29NO3, found 196.2 [M-Boc]+.

Provenance & Evidence