m-Chloroperbenzoic acid → 2-Ethyl-5-hydroxy-2,3-dihydro-benzofuran-2-carboxylic acid methyl ester

반응식

C([C:4]1[CH:5]=[CH:6][C:7]2[O:11][C@:10]([CH2:16][CH3:17])([C:12]([O:14][CH3:15])=[O:13])[CH2:9][C:8]=2[CH:18]=1)(=O)C.ClC1C=CC=C(C(OO)=[O:27])C=1.C([O-])(O)=O.[Na+]>ClCCl>[CH3:15][O:14][C:12]([C:10]1([CH2:16][CH3:17])[CH2:9][C:8]2[CH:18]=[C:4]([OH:27])[CH:5]=[CH:6][C:7]=2[O:11]1)=[O:13]

참가 물질

실험 절차

Methyl (2S)-5-acetyl-2-ethyl-2,3-dihydro-benzofuran-2-carboxylate (3.8 g, ca. 15 mmol), m-chloroperbenzoic acid (70%, 7.7 g, 30 mmol) and NaHCO3 (3.8 g, 45 mmol) in dichloromethane (150 mL) was stirred under reflux for 2 hrs. The reaction mixture was washed successively with saturated aqueous sodium sulfite (100 mL) and aqueous NaHCO3 (2×100 mL). After removal of solvent, the residue was dissolved in methanol (100 mL) and treated with aqueous KOH (5 N, 3 mL) at 0° C. for 5 min. The reaction was neutralized with excess solid sodium bicarbonate, filtered and concentrated. The residue was purified by chromatography on silica gel eluting with 8:2 hexane:ethyl acetate to give the title compound.