Cyanomethylenetributylphosphorane → tert-butyl (9aS)-3-(3-cyano-4-fluoro-2-methylphenyl)hexahydropyrazino[2,1-c][1,4]oxazine-8(1H)-carboxylate

Participants

Reaction Conditions

Reaction Steps

tert-Butyl (3S)-4-[2-(3-cyano-4-fluoro-2-methylphenyl)-2-hydroxyethyl]-3-(hydroxymethyl)piperazine-1-carboxylate (18.5 g, 47.0 mmol) and cyanomethylenetri-n-butylphosphorane (20.4 g, 85.0 mmol) were dissolved in 180 mL of benzene. The reaction mixture was degassed and heated to 100° C. for 16 h. LC-MS analysis indicated product peak (M+1=376). The reaction was cooled and evaporated to dryness. The residue was purified by chromatography through a 330 g Redi-sep column, eluting with a 20% acetone/80% hexane mixture to yield a cis-trans mixture of the title compound.

Provenance & Evidence