[OH:1][N:2]1[C:6](=[O:7])[C:5]2=[CH:8][CH:9]=[CH:10][CH:11]=[C:4]2[C:3]1=[O:12].[C:13]1(B(O)O)[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1.N1C=CC=CC=1>[Cu]Cl.ClCCCl>[O:1]([N:2]1[C:3](=[O:12])[C:4]2=[CH:11][CH:10]=[CH:9][CH:8]=[C:5]2[C:6]1=[O:7])[C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1A 20 mL scintillation vial was charged with N-hydroxyphthalimide (163 mg, 1.0 mmol), copper (I) chloride (99 mg, 1.0 mmol), freshly activated 4 Å molecular sieves (˜250 mg), and phenylboronic acid (244 mg, 2.0 mmol). 1,2-Dichloroethane (5 mL) was added followed by pyridine (90 μL, 1.1 mmol), resulting in a light brown suspension. The cap was loosely applied such that the reaction suspension was open to air and stirred at room temperature until completion as detected by analytical RP-HPLC (mixture color turned from brown to emerald green as the reaction proceeded). Upon completion (˜48 h), the mixture was adsorbed onto silica gel and concentrated to a powder. Flash chromatographic purification over silica (25% EtOAc in hexanes) afforded N-phenoxyphthalimide 9 as a white solid (216 mg, 90%); see below for characterization data.
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