3,4-dihydro-2H-pyran → (2R)-1-morpholino-2-((tetrahydro-2H-pyran-2-yl)oxy)propan-1-one

Participants

Reaction Steps

To a dichloromethane (500 ml) solution of N-[(2R)-2-hydroxypropionyl]morpholine (141 g) was added p-toluenesulfonic acid mono hydrate (1.67 g). To the mixture was added dropwise (30 minutes) 3,4-dihydro-2H-pyran (89.3 g) under ice-cooling, which was stirred for 30 minutes at room temperature. The reaction mixture was washed with a 5% aqueous solution of sodium hydrogen carbonate (150 ml×2), which was dried (magnesium sulfate), then the solvent was distilled off under reduced pressure. The residue was purified by means of a silica gel chromatography [silica gel 800 g, eluent: hexane-ethyl acetate=8:1→ethyl acetate] to give N-[(2R)-2-(3,4,5,6-tetrahydro-2H-pyran-2-yloxy)propionyl]morpholine (184 g) as a pale yellow oily product.

Provenance & Evidence