(3R)-3-butyl-1-phenylmethoxyazetidin-2-one

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of (3R)-3-butyl-1-[(phenylmethyl)oxy]-2-azetidinone (7) (52.8 g, 0.23 mol) in THF/MeOH (3:1, 1500 mL) at 0° C. was added Lithium hydroxide monohydrate (11.4 g, 0.27 mol) in water (375 mL). The mixture was warmed up to rt and stirred overnight. TLC indicated completion of the reaction. Organic solvents were removed under vacuum, and the aqueous solution was washed with DCM, acidified with 4 N HCl to pH ˜2.0, and extracted with DCM. The extracts were dried, filtered and concentrated to provide the title compound (40 g, 69%). LCMS: (M+H)+: 252.2. completion of the reaction Organic solvents were removed under vacuum the aqueous solution was washed with DCM extracted with DCM The extracts were dried filtered concentrated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of (2R)-2-(hydroxymethyl)-N-[(phenylmethyl)oxy]hexanamide (6) (52 g, 0.21 mol) and Ph3P (60 g, 0.23 mol) in THF (1500 mL) at 0° C. was added DIAD (41.8 g, 0.21 mol). The mixture was warmed up to rt and stirred overnight. TLC indicated completion of the reaction. THF was removed under vacuum. The residue was titurated with ethyl acetate/petroleum ether (1:10) and filtered. The filtrate was concentrated and the residue was purified by flash column chromatography to provide the title compound (52.8 g, 110%). LCMS: (M+H)+: 234.2. completion of the reaction THF was removed under vacuum filtered The filtrate was concentrated the residue was purified by flash column chromatography