反应详情

Into 120 ml of methanol were dissolved 293 mg (0.5 mmol) of [RuCl2(p-cymene)]2 and 360 mg (1.0 mmol) of (1R,2R)—N-tosyl-diphenylethylenediamine (hereinafter referred to as (R,R)-TsDPEN) to prepare a solution, and 0.27 ml (2.0 mmol) of triethylamine was dropwise added to the solution, followed by stirring for 0.5 hour at room temperature. To the reaction solution was dropwise added a solution prepared by dissolving 20 g (96 mmol) of o-nitrophenyl pyruvic acid into 80 ml of methanol, and 38.7 g (383 mmol) of triethylamine was furthermore dropwise added thereto. The bath was heated up to a temperature of 40° C., and then 13.2 g (278 mmol) of formic acid was dropwise added over 1 hour, followed by stirring for 2 hours at a bath temperature of 40° C. Upon completion of the reaction, the solvent was distilled off under reduced pressure. Thereto was added 40 ml of water, and then 22.6 g of concentrated hydrochloric acid was gradually dropwise added under ice cooling; thus, pH of the solution was adjusted to 2. Extraction was performed twice with 200 ml of ethyl acetate, and then the organic layer was washed with 20 ml of a saturated aqueous solution of sodium chloride, followed by concentration under reduced pressure. As a result, 27.0 g (yield 97%, 97% ee) of (2R)-hydroxy-3-(o-nitrophenyl)propanoic acid was obtained.

1. additionwas dropwise added to the solution
2. additionTo the reaction solution was dropwise added a solution
3. customprepared
4. additionwas furthermore dropwise added
5. temperatureThe bath was heated up to a temperature of 40° C.
6. stirringby stirring for 2 hours at a bath temperature of 40° C
7. customUpon completion of the reaction
8. distillationthe solvent was distilled off under reduced pressure
9. additionThereto was added 40 ml of water
10. addition22.6 g of concentrated hydrochloric acid was gradually dropwise added under ice cooling
11. extractionExtraction
12. washthe organic layer was washed with 20 ml of a saturated aqueous solution of sodium chloride
13. concentrationfollowed by concentration under reduced pressure