General procedure for the synthesis of (R)-1-(2-chlorophenyl)-1,2-ethanediol from methyl 2-(2-chlorophenyl)-2-oxoacetate: In an inert atmosphere glove box, the substrate methyl 2-(2-chlorophenyl)-2-oxoacetate (0.5 mmol), base (0.05 mmol), Ru-MACHO catalyst (5 μmol) and methanol (0.5 mL). The glass reactor was sealed and transferred to an autoclave, followed by replacing the air in the kettle with hydrogen three times. The reaction was carried out at 25°C or 80°C with constant stirring for 12-24 h under 10-50 bar hydrogen pressure. Upon completion of the reaction, the autoclave was cooled to room temperature. The residual hydrogen was slowly released in a fume hood and the reaction mixture was transferred to a conical flask containing deionized water (2 mL) and extracted with ethyl acetate (3 x 5 mL). The organic phases were combined, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to afford the pure target product (R)-1-(2-chlorophenyl)-1,2-ethanediol.
