Hydrochloric Acid → (S)-1-(3-Methylphenyl)-1,2-ethanediol 2-tosylate

Participants

Reaction Steps

To a stirred solutioll of (S)-1-(3-methylphenyl)-1,2-ethanediol (1.78 g, 11.7 mmol) in pyridine (35 ml) was added p-toluenesulfonyl chloride (2.46 g, 12.9 mmol), and 4-dimethylaminopyridine (1.58 g, 12.9mmol) at 0° C. and the reaction mixture was stirred at 0° C. to rt for 17 h. The reaction mixture was acidified with 6 N HCl aqueous solution and extracted with CH2Cl2. The extract was washed with water and brine, dried (Na2SO4), and concentrated to give 3.02 g of yellow oil, which was purified by column chromatography (silica gel: 100 g, ethyl acetatelhexane:1/9 to 1/3) to afford 2.63 g (73%) of desired product as light yellow oil. Its optical purity was 97% ee by HPLC employing a chiral stationary phase (chiral pak AS, Daicel Chemical Industries, eluted with n-hexane/EtOH:98/2; detection time:: 55 min for (R)-isomer 59 min for (S)-isomer).

Provenance & Evidence