Cyanomethylenetributylphosphorane → tert-butyl(9aS)-3-(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-(1-oxo-1,3-dihydro-2-benzofuran-5-yl)ethyl]piperazine-1-carboxylate (3.3 g, 8.4 mmol) and cyanomethylene tri-n-butylphosphorane (3.65 g, 15.1 mmol) were dissolved in 30 mL of benzene, the solution was degassed, and then heated to 100° C. for 3 h. LC-MS showed the product peak (M+1=389). The reaction mixture was cooled and evaporated to dryness. The residue was purified by MPLC through a 330 g Redi-sep column and eluted with a 15% acetone/85% hexane mixture to yield a cis-trans mixture of the title compound.

Provenance & Evidence