A solution of (S)-tert-butyl 2-(hydroxymethyl)morpholine-4-carboxylate (1.0 equiv.), tosyl chloride (1.10 equiv.), triethylamine (1.40 equiv.) and N,N-dimethylpyridin-4-amine (0.1 equiv.) in dichloromethane (0.1 M) at RT. The resulting mixture was stirred at RT for 2 hours. The reaction mixture was then diluted with water and the aqueous layer was separated and washed sequentially with NaOH (1 M), water, brine dried over sodium sulfate then concentrated in vaccuo to yield (S)-tert-butyl 2-((tosyloxy)methyl)morpholine-4-carboxylate as a pale yellow oil in 99% yield. LCMS (m/z) (M+H)=390.2, Rt=0.84 min.
