Hydrochloric Acid → 3-Ethyl-6-(methyloxy)-2-phenyl-3,4-dihydro-1(2H)-naphthalenone

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Reaction Steps

To a solution of 3-{[3-(methyloxy)phenyl]methyl}-2-phenylpentanoic acid (54) (0.98 g, 3.28 mmol) in CH2Cl2 (20 mL) at room temperature was added oxalyl chloride (0.88 mL, 9.85 mmol) followed by one drop of DMF. The mixture was stirred at room temperature overnight. CH2Cl2 and excess of oxalyl chloride were removed under vacuum. The residue was dissolved in CH2Cl2 (30 mL), cooled in an ice bath, AlCl3 (0.67 g, 4.93 mmol) was added. The resulting brown solution was stirred at 0° C. for 5 h. Poured into 1 N HCl (35 mL) with ice, and the mixture was extracted with CH2Cl2. The extracts were combined and washed with brine, dried over Na2SO4, filtered, and the filtrate was concentrated to give the crude product as a yellow oil. The crude product was purified by flash chromatography over SiO2 with hexanes:EtOAc (6.5:1) to give 0.84 g (91%) of the title compound (55) as a greenish-yellow oil. 1HNMR indicated it was a mixture of two diastereomers with a ratio of 2:1.

Provenance & Evidence