2-Naphthalenesulfonyl chloride → di-tert-butyl 4-{3-[(2-naphthylsulfonyl)oxy]propyl}-N-trityl-L-glutamate

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Reaction Conditions

Reaction Steps

At 0° C. triethylamine (0.68 mL, 4.90 mmol) and naphthalene-2-sulfonyl chloride (0.370 g, 1.63 mmol) were added to a solution of di-tert-butyl 4-(3-hydroxypropyl)-N-trityl-L-glutamate (0.457 g, 0.816 mmol) in dichloromethane (10 mL). The resulting mixture was stirred at 0° C. for 2 h and for 16 h at room temperature. The solution was concentrated and the crude product was purified by flash chromatography (silica, ethyl acetate/hexane) to afford di-tert-butyl 4-{3-[(2-naphthylsulfonyl)oxy]propyl}-N-trityl-L-glutamate (0.479 mg, 78%) as a mixture of (4S,4S)/(2S,4R) diastereoisomers. The isomers were separated by chiral HPLC (Chiralpak IC 5 μm 250×30 mm, ethanol/methanol 1:1, 30 mL/min):

Provenance & Evidence