(E)-N-methoxy-N-methyl-3-(3-cyclopentoxy-4-methoxyphenyl)-prop-2-enamide → (E)-5-(3-cyclopentoxy-4-methoxyphenyl)-pent-4-en-3-one

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Reaction Steps

To a solution of (E)-N-methoxy-N-methyl-3-(3-cyclopentoxy-4-methoxyphenyl)-prop-2-enamide (1.33 g, 4.36 mmol) in 8.0 mL of THF cooled to 0° C. was added CH3CH2MgBr (9 mL of 1.0M THF solution). The resulting solution was stirred for 30 min, diluted with ether and transferred to a separatory funnel. After washing with H2O, 1M H3PO4, and brine, the organic layer was dried over MgSO4, filtered, and concentrated under reduced pressure. Silica gel chromatography (4:1, hexanes:ethyl acetate) provided (E)-5-(3-cyclopentoxy-4-methoxyphenyl)-pent-4-en-3-one as a white solid (400 mg, 34%). 1H-NMR (300 MHz): δ 1.17 (t, 3, J=7.6), 2.69 (q, 2, J=7.3), 3.89 (s, 3), 6.59 (d, 1, J=16), 7.50 (d, 1, J=16). Anal. Calcd for C17H22O3 : C, 74.42; H, 8.08. Found: C, 74.52; H, 8.13.

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