HCID 15748060, compound → HCID 11107979, compound

Participants

Reaction Steps

t-Butyl 5-(1-benzyloxy-2-oxo-4-azetidinyl)-3-oxopentanoate (90 mg, 0.26 mmol) was hydrogenated with 10% Pd/C in EtOAc for 1.5 h to yield t-butyl 5-(1-hydroxy-2-oxo-4-azetidinyl)-3-oxopentanoate (A). Compound A was directly taken on to the next step without undue delay. In an ice bath under argon atmosphere, compound A was dissolved in 1 mL of anhydrous CH3CN. The p-carboxybenzenesulfonyl azide (68.0 mg, 0.30 mmol, 110 mol %) was added as a solid followed by 1 mL of solvent as a wash and Et3N (125 microliter, 91 mg, 0.90 mmol, 330 mol %). The reaction was stirred at ice bath temperature and was gradually allowed to warm to ambient temperature over 1-2 h, and was stirred for a total of 27 h. The reaction eventually turned light brown and a white precipitate formed. The reaction mixture was diluted with 15 mL of CH2Cl2 and 35 mL of ether, and the solvent was evaporated after filtration to remove the solid. The resulting brown oil was passed through a short plug of silica as a solution in CH2Cl2 to yield 50 mg of a light brown oil after solvent removal. The oil was chromatographed by column (EtOAc and hexanes as eluting solvents) to yield two fractions as oils: compound B (13 mg, 16% overall yield) and compound C (13 mg, 17% overall yield). The diazo/azido/reduced product B was recrystallized in ether/hexanes to give orange-yellow needles on which X-ray crystallographic data were obtained.

Provenance & Evidence