Triphenylphosphine → 2-[4-(4-Fluoro-benzyloxy)-benzenesulfonylamino]-oxo-heptanoic acid tert-butyl ester

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Reaction Steps

To a mixture of acetyl propanol (0.39 mL, 3.8 mmol), [4-(4-fluoro-benzyloxy)-benzenesulfonylamino]-acetic acid tert-butyl ester (1.0 g, 2.53 mmol) and tetrahydrofuran (8 mL) was added triphenylphosphine (1.0 g, 3.8 mmol) and diethylazodicarboxylate (0.60 mL, 3.8 mmol). After stirring for 6 h at room temperature, the mixture was treated with additional acetyl propanol (0.15 mL), triphenyl phosphine (0.30 g) and diethylazodicarboxylate (0.20 mL). After stirring for 30 min, the mixture was concentrated in vacuo, and the residue was purified by silica gel chromatography eluting with 4:1 to 2:1 hexane-ethyl acetate, giving 0.70 g of 2-[4-(4-fluoro-benzyloxy)-benzenesulfonylamino]-oxo-heptanoic acid tert-butyl ester as a colorless solid:

Provenance & Evidence