Cyanomethylenetributylphosphorane → tert-butyl(9aS)-3-(4-methyl-1-oxo-1,3-dihydro-2-benzofuran-5-yl)hexahydropyrazino[2,1-c][1,4]oxazine-8(1H)-carboxylate

Participants

Reaction Conditions

Reaction Steps

tert-Butyl(3S)-3-(hydroxymethyl)-4-[2-hydroxy-2-(4-methyl-1-oxo-1,3-dihydro-2-benzofuran-5-yl)ethyl]piperazine-1-carboxylate (3.3 g, 8.2 mmol) and cyanomethylene tri-n-butylphosphorane (2 equivalents) were dissolved in 45 mL benzene in a sealed and degassed tube. The mixture was heated to 100° C. for 3 h. The reaction mixture was cooled and evaporated to dryness. The residue was purified by chromatography through a 330 g Redi-sep column and eluted with 30% acetone/70% hexane mixture to yield the title compound as a cis-trans mixture. LC-MS: M+1=389.

Provenance & Evidence