Triphenylphosphine → tert-Butyl [[6-[(4-chlorophenylsulfonyl)(2,5-difluorophenyl)methyl]pyridin-3-yl]methyl]-N-(tert-butoxycarbonyl)carbamate

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Reaction Steps

Under a nitrogen atmosphere, diisopropyl azodicarboxylate (128 μl, 0.653 mmol) was added to a tetrahydrofuran (5 ml) solution of the 2-[(4-chlorophenylsulfonyl)(2,5-difluorophenyl)methyl]-5-(hydroxymethyl)pyridine (178 mg, 0.435 mmol) obtained in Example 43, di-t-butyl iminodicarboxylate (142 mg, 0.653 mmol) and triphenylphosphine (171 mg, 0.653 mmol). The resulting mixture was stirred at room temperature for 5 hours. Water was added to the reaction mixture, followed by extraction with ethyl acetate. The organic layer was washed sequentially with water and brine. The resulting organic layer was dried over sodium sulfate and then, concentrated under reduced pressure. The residue thus obtained was subjected to flash silica gel column chromatography, and the fraction obtained from the hexane:ethyl acetate=4:1 eluate was concentrated under reduced pressure to give the title compound (78 mg, 0.128 mmol, 32%) as a colorless oil.

Provenance & Evidence