Hydrochloric Acid → 1,3-Dioxacyclopent-4-ylmethyl p-Toluenesulfonate

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Reaction Steps

p-Toluenesulfonyl chloride (76.2 g, 0.4 mole) was added to a solution of 104.1 g (1 mole) glycerol formal (a mixture comprised of 67% 1,3-dioxacyclohex-5-ol and 33% (1,3-dioxacyclopent-4-yl)methanol) in 1000 ml. pyridine cooled to 0° C. under nitrogen. After standing at 0° C. for 20 hr. the reaction mixture was allowed to warm to room temperature and added to 1500 ml. of 6N aqueous hydrochloric acid. The resulting mixture was extracted with four 500 ml. portions of ethyl acetate. The combined ethyl acetate extracts were washed with two 500 ml. portions of 6N aqueous hydrochloric acid solution, two 500 ml. portions of water and 500 ml. saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate and concentrated in vacuo. The oily product (78.4 g) consisted of ca a 2:1 mixture of 1,3-dioxacyclopent-4-ylmethyl tosylate and 1,3-dioxacyclohex-5-yl tosylate which was used without purification in a subsequent step (Preparation K).

Provenance & Evidence