Reaction #2122523

Reaction equation

(S)-benzyl 2-hydroxy-2-phenylacetate

triethylamine

p-toluenesulfonyl chloride

→

benzyl 2-phenyl-2-(tosyloxy)acetate

Solvents

CH2Cl2

CH2Cl2

Conditions

Workup

1. 1
   Temperaturewhile maintaining the temperature between −5° C. and 0° C
2. 2
   workup.WAITstored in a freezer (−25° C.) for 14 hours
3. 3
   Otherthaw to ambient temperature
4. 4
   Washwashed with water (200 mL), 1N HCl (100 mL) and brine (100 mL)
5. 5
   Dryingdried (MgSO4)
6. 6
   Filtrationfiltered
7. 7
   Concentrationconcentrated in vacuo

Procedure

A CH2Cl2 (200 mL) solution of p-toluenesulfonyl chloride (8.65 g, 45.4 mmol) was added dropwise to a cooled (−5° C.) CH2Cl2 (200 mL) solution of (S)-benzyl 2-hydroxy-2-phenylacetate (10.0 g, 41.3 mmol), triethylamine (5.75 mL, 41.3 mmol) and 4-dimethylaminopyridine (0.504 g, 4.13 mmol), while maintaining the temperature between −5° C. and 0° C. The reaction was stirred at 0° C. for 9 hours, and then stored in a freezer (−25° C.) for 14 hours. It was allowed to thaw to ambient temperature and washed with water (200 mL), 1N HCl (100 mL) and brine (100 mL), dried (MgSO4), filtered, and concentrated in vacuo to provide benzyl 2-phenyl-2-(tosyloxy)acetate as a viscous oil which solidified upon standing (16.5 g). The chiral integrity of the product was not checked and that product was used for the next step without further purification. 1H NMR (DMSO-d6, δ=2.5, 500 MHz) δ 7.78 (d, J=8.6, 2H), 7.43-7.29 (m, 10H), 7.20 (m, 2H), 6.12 (s, 1H), 5.16 (d, J=12.5, 1H), 5.10 (d, J=12.5, 1H), 2.39 (s, 3H). RT=3.00 (Cond. 3); >90% homogeneity index; LC/MS: Anal. Calcd. for [M+H]+ C22H20NaO5S: 419.09; found 419.04.

Source