[N+:1]([C:4]1[CH:9]=[CH:8][C:7]([CH2:10][CH2:11][C:12](=[O:17])[CH2:13][C:14](=[O:16])[CH3:15])=[CH:6][CH:5]=1)([O-])=O.[Si]([CH:22]([OH:29])[CH:23](O)[Si](C)(C)C)(C)(C)C.[Si](OS(C(F)(F)F)(=O)=O)(C)(C)C.[H][H].[CH3:44][CH2:45][O:46]C(C)=O>C(Cl)Cl>[CH3:15][C:14]1([CH2:13][C:12]2([CH2:11][CH2:10][C:7]3[CH:8]=[CH:9][C:4]([NH2:1])=[CH:5][CH:6]=3)[O:17][CH2:23][CH2:22][O:29]2)[O:46][CH2:45][CH2:44][O:16]1A clean oven dried flask was charged with the 6-(4-nitro-phenyl)-hexane-2,4-dione (3.7 g, 15.72 mmol), dry CH2Cl2 (20 ml) followed by bisTMS ethylene glycol (38.5 ml, 157.3 ml) were added to the flask and the resulting solution was cooled to −5° C. with stirring under argon. TMSOTf (300 μl) was added to the reaction mixture and the solution was stirred at −5° C. for 6 h. Reaction was quenched with pyridine (10 ml) and poured into sat. NaHCO3. The mixture was extracted with EtOAc and the organic layer was washed with water, brine, dried (Na2SO4) and concentrated to give a yellow solid. The solid was triturated with hexanes to give a free flowing pale yellow solid (3.5 g, 72%) which was dissolved in EtOAc (50 ml) and hydrogenated on a Parr shaker starting with 50 psi of hydrogen pressure. After two hours the reaction was filtered through a pad of celite, the celite was washed thoroughly with CH2Cl2MeOH and combined organics were concentrated to give title compound (1.46 g, 100%) as an oil that solidifies upon standing.
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