ethyl (2R)-2-methylsulfonyloxypropanoate

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of (R)-ethyl 2-(methylsulfonyloxy)propanoate (15 g, 0.076 mol) in DMF (300 ml) was added dibenzyl malonate (21.5 g, 0.076 mol) and CsF (11.5 g, 0.076 mol). The mixture was heated to 50° C. for 2 days. After cooled to room temperature, the mixture was poured into water and then extracted with EtOAc. The organic phase was washed with brine, water and dried. Concentrated to afford (R)-1,1-dibenzyl 2-ethyl propane-1,1,2-tricarboxylate, which was purified by silica gel chromatography (11 g, 40%). After cooled to room temperature extracted with EtOAc The organic phase was washed with brine, water dried Concentrated

Conditions: temp:12.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: (R)-ethyl 2-hydroxypropanoate (15 g, 0.127 mol) and TEA (15.4 g, 0.15 mol) were added to THF and then cooled to 10-15° C. Then MsCl (15 g, 0.13 mol) was added to the solution dropwise with cooling while maintaining the temperature in the range of 10-15° C. at about 2 hours. The mixture was allowed to warm to about 20° C. and the solid was filtered off. The solution was washed with water and dried, concentrated to afford (R)-ethyl 2-(methylsulfonyloxy)propanoate (15 g, 60%). 1H NMR (400 MHz, CDCl3) δ ppm, 5.11-5.14 (q, 1H), 4.24-4.29 (m, 2H), 2.81-3.17 (q, 3H, J=7.2 Hz), 1.61-1.43 (d, 3H, J=7.6 Hz), 1.30-1.32 (m, 3H). with cooling while maintaining the temperature in the range of 10-15° C. at about 2 hours to warm to about 20° C. the solid was filtered off The solution was washed with water dried concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: (R)-2-[4-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]propionic acid is prepared as follows: A suspension of ethyl (R)-2-mesyloxypropionate (0.392 g, 2.0 mmol), 4-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenol (0.578 g, 2.0 mmol) and potassium carbonate (0.276 g, 2.0 mmo.) in 8 ml of DMSO is heated at 80° for 24 hours. The reaction mixture is cooled and worked up to give ethyl (R)-2-[4-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]propionate. The propionate is hydrolyzed by stirring it (0.80 g, 2.22 mmol) in 10 ml of ethanol with sodium hydroxide (0.10 g, 2.50 mmol) in 1 ml of water overnight. The ethanol is then removed in vacuo from the reaction mixture. The residue is acidified with HCl and extracted with ether. The organic fraction is washed with brine until neutral and dried over sodium sulfate. Solvent is removed to give (R)-2-[4-(3-chloro-5-trifluoromethyl-2-pyridyloxy)phenoxy]propionic acid. is heated at 80° for 24 hours The reaction mixture is cooled