Ethanol → 4-Phenylcyclohexyl 4-methylbenzenesulfonate

Participants

Reaction Conditions

Reaction Steps

Commercial chloroform (Aldrich) is freed from stabilizing ethanol by passing the chloroform through a column of alumina. 4-Phenylcyclohexanol (28.3 g; 160 mmol.) is dissolved in the chloroform (150 mL) and the resulting solution is cooled in an ice bath (0° C.). Pyridine (25.3 g; 25.9 mL; 320 mmol.) is added to the solution, followed by the addition of p-toluenesulfonyl chloride (45.8 g; 240 mmol.) in small portions with constant stiffing. The reaction mixture is left overnight. TLC (hexane-ethyl acetate 15:1) shows that the starting 4-phenylcyclohexanol is consumed completely. Ether (500 mL) and water (150 mL) are added, and the organic layer is washed successively with 300 mL of 2N HCl, 5% NaHCO3, and water and then dried with Na2SO4. TLC exhibits three spots, the major one having the lowest Rf. The solvent is removed in a rotary evaporator, and the crude tosylate (70.4 g) is dissolved in 125 mL of hexane-ethylacetate (4:1) mixture upon heating and then left to crystallize in the freezer at −20° C. White product is collected and dried in vacuum, yield 40.6 g (76%), identified as 4-phenylcyclohexyl 4-methylbenzenesulfonate. TLC (hexane-ethyl acetate 15:1)—one spot, Rf=0.16. 1H NMR CDCl3, ppm): 1.2-2.2 (m, 8H, cyclohexyl), 2.46 (s, 3H, CH3), 2.48 (m, 1H, PhCH), 4.50 (m, 1H, TsOCH), 7.1-7.3 (m, 5H, Ph), 7.35 and 7.83 (two d, J=8.1 Hz, 4H, C6H4).

Provenance & Evidence