Iodine → 4,4-Dimethoxytetrahydro-2H-pyran-3-ol

Participants

Reaction Steps

A 12-L 4-neck round bottom flask with an overhead stirrer was charged with MeOH (8.18 L) and potassium hydroxide (400.5 g, 2.4 mol) while stirring at room temperature until base was completely dissolved (an exotherm was observed). The homogeneous mixture was cooled to 0° C. with an ice-acetone bath. To a 500-mL addition funnel was charged with tetrahydro-4H-pyran-4-one (250 g, 2.5 mol) and after the KOH-methanol solution temperature reached 0° C., the pyranone was added drop wise while maintaining temperature at <5° C. After stirring for an additional 1.5 h, iodine (704 g, 1.1 mol) was added portion wise over a 1.5 h period while maintaining the temperature at <5° C. The reaction mixture was allowed to stir at room temperature for 18 h. The reaction was concentrated and the remaining residue was treated with toluene (1.5 L) and stirred for ½ h. A solid had precipitated, was filtered off and the filtrate was evaporated to afford to afford the title compound (330 g, 81%) as an amber oil.

Provenance & Evidence