4-Toluenesulfonyl chloride → Pent-2-yn-1-yl 4-methylbenzene-1-sulfonate

Participants

Reaction Conditions

Reaction Steps

A solution of 2-pentyn-1-ol (8.40 g, 100 mmol) in THF (60 mL) was treated with p-toluenesulfonyl chloride (23.9 g, 125 mmol) at -10° C., followed by pulverized KOH (11.3 g, 200 mmol) without allowing the temperature to exceed -5° C. After 1.5 hours of stirring at -10° C., 50 mL of saturated brine was added and the product extracted into CH2Cl2. The product, 2-pentyn-1-yl p-toluenesulphonate (2), was isolated by flash chromatography (18.17 g 76.4% yield). 1H NMR (200 MHz) δ: 7.81 (d, J=8.4 Hz, 2H, arom. CH), 7.33 (d, J=7.9 Hz, 2H, arom. CH), 4.68 (t, J=2.2, 2.2 Hz, 2H, CH2O-1), 2.44 (s, 3H, arom. CH3), 2.13 (tq, J=2.2, 2.2, 2.2, 7.5, 7.5 Hz, 2H, CH2 -4), 1.00 (t, J=7.5, 7.5 Hz, 3H, CH3 -5).

Provenance & Evidence