Pyridine → (Tetrahydro-2H-pyran-4-yl)methyl 4-methylbenzenesulfonate

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Reaction Steps

p-Toluenesulfonyl chloride (29.8 g, 157 mmol) was added portionwise to a mixture of tetrahydro-2H-pyran-4-yl-methanol (20.0 g, 172 mmol) and pyridine (25.2 ml, 313 mmol) in dichloromethane (200 ml). The mixture was stirred at room temperature for 17 h, then quenched with aqueous hydrochloric acid (2 M; 100 ml). The layers were separated and the aqueous layer extracted with dichloromethane (2×100 ml). The organic layers were combined and concentrated in vacuo. Recrystallisation from dichloromethane: n-heptane (5:1) afforded toluene-4-sulfonic acid tetrahydro-pyran-4-ylmethyl ester. The mother liquors were further purified by silica gel column chromatography eluting with 50% dichloromethane in n-heptane to yield a further quantity of toluene-4-sulfonic acid tetrahydro-pyran-4-ylmethyl ester (total yield 41.6 g, 154 mmol).

Provenance & Evidence