To a solution of intermediate (b), N-benzyl-2-(2-Fluoro-3-methyl-benzyl)-morpholin-3-one (275 mg, 0.876 mmol) in tetrahydrofuran (10 mL) at 0° C. was added BH3 (1M in tetrahydrofuran, 2.63 mL, 2.63 mmol). The mixture was stirred at 23° C. for 1 h then heated to reflux for 18 h, cooled to 23° C. and stirred vigorously with Rochelle's salt solution (15 mL) for 1.5 h. Ethyl acetate (30 mL) was added and stirring continued for 1.5 h. The organic phase was separated, dried (Na2SO4) and concentrated affording intermediate (a), N-benzyl-2-(2-fluoro-3-methyl-benzyl)-morpholine, as a pale yellow oil (190 mg, 73%).
