Triphenylphosphine → tert-Butyl(2R,5S)-5-azido-2-[2-(6-cyano-3-oxo-2,3-dihydro-4H-1,4-benzoxazin-4-yl)ethyl]piperidine-1-carboxylate

Participants

Reaction Steps

To a solution of tert-butyl (2R,5R)-2-[2-(6-cyano-3-oxo-2,3-dihydro-4H-1,4-benzoxazin-4-yl)ethyl]-5-hydroxypiperidine-1-carboxylate (Intermediate 185, crude, 0.8 g) in THF (20 mL) were successively added triphenylphosphine (1.30 g), diisopropylazodicarboxylate (1 mL) and diphenyl phosphoryl azide (0.90 g). After 4 hours, the reaction was diluted with ethyl acetate, washed with saturated solution of sodium hydrogen carbonate (NaHCO3) and brine, dried over sodium sulfate and concentrated. Chromatography on silica gel with a gradient of 0-5% methanol in methylene chloride gave 0.31 g of product.

Provenance & Evidence