4-(Iodomethyl)tetrahydro-2H-pyran is prepared from 4-(methanesulfonyloxymethyl)tetrahydropyran by heating and refluxing under conditions of reaction with sodium iodide in acetone. The specific method of operation is described below:
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Preparation: A mixture of Preparation (328g, 1.69mol) and sodium iodide (507g, 3.4mol) in acetone (3.3L) was refluxed for 4h. TLC (diethyl ether) showed significant mesylate remaining so further sodium iodide (127g, 0.65mol) was added and reflux continued for 16h. The mixture was cooled and filtered. The resulting cake was washed with acetone, dried, and11then partitioned between diethyl ether (800mL) and water (800mL). The aqueous phase was re-extracted with diethyl ether (200mL), the ether extracts combined and washed with 10% sodium thiosulphate solution (300mL) which decolourised the extract. Final washing with water (300mL), drying (MgS04) and then removal of the solvent provided the 4-(IODOMETHYL)TETRAHYDRO-2H-PYRAN (365g, 92% yield).
