[C:1]([O:4][C:5]1[CH:10]=[CH:9][C:8](/[CH:11]=[CH:12]/[C:13]([O:15][CH3:16])=[O:14])=[CH:7][CH:6]=1)(=[O:3])[CH3:2].[N+](=[CH2:19])=[N-].CN(N=O)C(N[N+]([O-])=O)=N.[OH-].[K+]>O1CCCC1.C(OCC)C.C(O)(=O)C.C([O-])(=O)C.[Pd+2].C([O-])(=O)C>[C:1]([O:4][C:5]1[CH:10]=[CH:9][C:8]([CH:11]2[CH2:19][CH:12]2[C:13]([O:15][CH3:16])=[O:14])=[CH:7][CH:6]=1)(=[O:3])[CH3:2]A solution of methyl (2E)-3-[4-(acetyloxy)phenyl]acrylate (2.20 g, 10.0 mmol) in tetrahydrofuran (200 mL) was stirred under ice-cooling, and a solution of diazomethane, prepared from N-methyl-N′-nitro-N-nitrosoguanidine (50% water-containing product, 7.50 g, 51.0 mmol) and aqueous potassium hydroxide (6.28 g, 112 mmol) solution (10.5 mL), in diethyl ether (75 mL) and palladium(II) acetate (0.150 g, 0.668 mmol) were alternately added thereto over 10 min in small portions. The reaction mixture was stirred for 2 hr under ice-cooling, and acetic acid (3 drops) was added. The insoluble material was filtered off through celite, and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate:hexane=5:95-40:60) to give the title compound (2.26 g, yield 97%) as a colorless oil.
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