Methanol → HCID 86745595, compound

Participants

Reaction Steps

To a solution of (4S)-3,3-diethyl-1-[(R)-α-n-propyl-(4-methyl)-benzylaminocarbonyl)]-4-(4-carboxyphenoxy)-azetidin-2-one (1.04 g, 2.30 mmol) in tetrahydrofuran (20 mL) cooled to 0° C. was added dropwise with stirring under a nitrogen atmosphere a 2.0M solution of borane-methyl sulfide in tetrahydrofuran (3.0 mL, 6 mmol). The solution was allowed to attain room temperature and stirred overnight. Excess borane was decomposed by slow addition of methanol. The solution was evaporated, and the crude product was subjected to flash chromatography on silica gel using 30% ethyl acetate in hexane as the mobile phase. (4S)-3,3-Diethyl-1-[(R)-α-n-propyl-(4-methyl)-benzylaminocarbonyl)]-4-[4-(hydroxymethyl)-phenoxy]-azetidin-2-one was obtained as a colorless oil. Triphenylphosphine (637 mg, 2.43 mmol) was dissolved in acetonitrile (11 mL) and bromine (0.12 mL) was added with stirring to give rise to a yellow-orange solution. Additional triphenylphosphine was added until a faintly yellow solution was obtained. A solution of (4S)-3,3-diethyl-1-[(R)-α-n-propyl-(4-methyl)-benzylaminocarbonyl]-4-[4-(hydroxymethyl)-phenoxy]-azetidin-2-one (1.0 g, 2.28 mmol) in acetonitrile (10 mL) was added dropwise with stirring. The reaction mixture was stirred ovenight at room temperature, evaporated, and the crude mixture subjected to flash chromatography on silica gel using 5% ethyl acetate in hexane as the mobile phase.

Provenance & Evidence