C(=O)([O-])[O-].[Cs+].[Cs+].[C:7]([O:11][C:12]([N:14]1[CH2:19][CH2:18][CH:17]([C:20]([C:23]2[S:24][C:25]([CH2:29][O:30][CH3:31])=[CH:26][C:27]=2Br)=[N:21][OH:22])[CH2:16][CH2:15]1)=[O:13])([CH3:10])([CH3:9])[CH3:8]>COCCO.[Cu](I)I>[C:7]([O:11][C:12]([N:14]1[CH2:19][CH2:18][CH:17]([C:20]2[C:23]3[S:24][C:25]([CH2:29][O:30][CH3:31])=[CH:26][C:27]=3[O:22][N:21]=2)[CH2:16][CH2:15]1)=[O:13])([CH3:10])([CH3:9])[CH3:8]Add cesium carbonate (1.13 g, 3.46 mmol, 1.50 equivalents) and copper iodide (44 mg, 0.23 mmol, 0.10 equivalents) to a stirred solution of 4-[1-(3-bromo-5-methoxymethyl-thiophen-2-yl)-1-hydroxyimino-methyl]-piperidine-1-carboxylic acid tert-butyl ester (1.00 g, 2.31 mmol, 1.00 equivalents) in 2-methoxy ethanol (23.30 mL). Stir the resulting mixture at room temperature overnight or up to 3 days and filter through celite. Evaporate the filtrate, partition the residue between ethyl acetate (70 mL) and water (23 mL) and separate. Extract the aqueous layer with ethyl acetate (3×70 mL), combine the organic layers, dry over magnesium sulfate, filter and evaporate. Purify the residue via flash column chromatography eluting with a mixture of hexane:ethyl acetate (4:1) to yield the desired product as a yellow oil. LC/MS (ESI), m/e 375 (MNa+), retention time 1.98 minutes. Condition II.
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