p-Toluenesulfonic acid → (R)-2-(tetrahydro-pyran-2-yloxy)-propionic acid methyl ester

Participants

Reaction Steps

Methyl (R)-(+)-lactate (25.0 g) was dissolved in dichloromethane (250 ml), to which was added, under ice-cooling, p-toluenesulfonic acid.hydrate (456 mg). To the mixture was then added dropwise 3,4-dihydro-2H-pyran (24.2 g) during 30 minutes, which was stirred for one hour under ice-cooling. To the reaction mixture was added a 5% aqueous solution of sodium hydrogen carbonate (50 ml), and the mixture was stirred vigorously, followed by separating the organic layer. The organic layer was further washed with a 5% aqueous solution of sodium hydrogen carbonate, which was dried over anhydrous magnesium sulfate, followed by distilling off the solvent under reduced pressure to leave methyl (2R)-2-(3,4,5,6-tetrahydro-2H-pyran-2-yloxy)propionate (42.7 g) as a pale yellow oily product.

Provenance & Evidence