Reaction #50178

Reaction equation

4-methoxy-4-[3-(tetrahydropyran-2-yloxy)-prop-1-ynyl]tetrahydropyran

pyridinium p-toluenesulfonate

→

4-methoxy-4-(3-hydroxyprop-1-ynyl)tetrahydropyran

Yield 47.6%

Solvents

methanol

Conditions

Workup

1. 1
   OtherThe volatiles were removed in vacuo
2. 2
   workup.DISSOLUTIONthe residue was dissolved in ethyl acetate
3. 3
   workup.ADDITIONtreated with saturated aqueous NH4Cl
4. 4
   DryingThe organic layer was dried over MgSO4
5. 5
   Filtrationfiltered
6. 6
   Concentrationconcentrated in vacuo
7. 7
   OtherPurification by chromatography on silica gel (100 g, 30% ethyl acetate: hexanes)

Procedure

To a solution of 4-methoxy-4-[3-(tetrahydropyran-2-yloxy)-prop-1-ynyl]tetrahydropyran (3.8 g, 14.8 mmol), prepared as in step 2, in methanol (50 mL), was added a catalytic amount of pyridinium p-toluenesulfonate (PPTS). The resulting yellow solution was stirred under nitrogen for 17 hours at ambient temperature. The volatiles were removed in vacuo and the residue was dissolved in ethyl acetate and treated with saturated aqueous NH4Cl. The organic layer was dried over MgSO4, filtered, and concentrated in vacuo. Purification by chromatography on silica gel (100 g, 30% ethyl acetate: hexanes) provided 4-methoxy-4-(3-hydroxyprop-1-ynyl)tetrahydropyran (1.2 g, 47 %) as a colorless oil.

Source