GENERAL STEPS: A tetrahydrofuran (THF, 100 mL) solution of lithium aluminum hydride (LAH, 2 eq.) was cooled to 0 °C in an ice bath under nitrogen protection. A solution of (R)-5-methylmorpholin-3-one (1 eq.) in THF (20 mL) was slowly added dropwise. After the dropwise addition, the reaction mixture was stirred at room temperature for 16 hours. Upon completion of the reaction, the mixture was cooled again to 0 °C and quenched by careful addition of water (2 mL), 2N sodium hydroxide solution (2 mL) and water (8 mL) in that order. After quenching, the resulting slurry was stirred at room temperature for 1 hour and then filtered through diatomaceous earth. The filter cake was washed with ethyl acetate and discarded. The filtrate was dried with anhydrous sodium sulfate, separated and concentrated to give (R)-3-methylmorpholine as a colorless oil.
