N-Methoxy-N-methyl-2-(2-methylphenyl)acetamide → 1-(2-Methylphenyl)but-3-en-2-one

Participants

Reaction Conditions

Reaction Steps

To a solution of vinylmagnesium bromide (220 mL, 1.0 M, 220 mmol) in 100 mL THF, was added dropwise under nitrogen atmosphere at 0° C. a solution of 2-(2-methylphenyl)-N-methoxy-N-methylacetamide (Step A, 21 g, 106.6 mmol) in ˜150 mL dry ether. The reaction mixture was stirred at 0° C. for 0.5 hr then poured slowly into an ice/2N aq HCl (300 mL) mixture. The resulting mixture was diluted with ether, transferred to a separation funnel. The organic layer was separated, washed with brine, dried over MgSO4, filtered and the solvent evaporated under vacuum to give 14.2 g of the crude title compound which was used without further purification. 1H-NMR (CDCl3): δ: 7.15-7.25 (4H, m), 6.47 (1H, dd, J1=14.2 Hz, J2=11 Hz), 6.35 (1H, d, J=14.2 Hz), 5.86 (1H, d, J=11 Hz), 3.83 (2H, s), 2.28 (3H, s).

Provenance & Evidence