[CH2:1]([O:3][P:4]([C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[OH:15])(=[O:8])[O:5][CH2:6][CH3:7])[CH3:2].[I-:16].[Na+].CC1C=CC(S([N-]Cl)(=O)=O)=CC=1.O.O.O.[Na+].Cl>CN(C=O)C.O>[CH2:6]([O:5][P:4]([C:9]1[CH:14]=[C:13]([I:16])[CH:12]=[CH:11][C:10]=1[OH:15])(=[O:8])[O:3][CH2:1][CH3:2])[CH3:7]To a cooled (0° C.) mixture of (2-hydroxy-phenyl)-phosphonic acid diethyl ester (13.1 g, 56.9 mmol) and sodium iodide (10.2 g, 68.3 mmol) in DMF (200 mL) was added chloramine-T trihydrate (19.2 g, 68.3 mmol) over 5 min. After 10 min, the reaction was allowed to warm to rt and the mixture was allowed to stir at rt for 2 h. The mixture was diluted with H2O (50 mL), acidified using 0.5 N HCl and extracted twice with EtOAc. The organic extracts were pooled and washed sequentially with satd. Na2S2O3/brine (1/1) and then brine. The organic layer was dried over anhydrous Na2SO4 and concentrated under reduced pressure. The residue was chromatographed over silica gel (elution with a stepwise gradient 5-15% EtOAc-hexanes) to give 14.9 g (73%) of a colorless solid after recrystallization (EtOAc-hexanes). Rf 0.30 (20% EtOAc-hexanes). Electrospray Mass Spectrum (50/50 acetonitrile/water) m/z 357 (M+H).
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