Catalytic Bismuth(V)-Mediated Oxidation of Hydrazones into Diazo Compounds

Nour Tanbouza, Laurent Caron, Azadeh Khoshoei and Thierry Ollevier*

*Département de Chimie, Université Laval, 1045 avenue de la Médecine, Québec, Québec G1V 0A6, Canada, Email: thierry.ollevierchm.ulaval.ca

N. Tanbouza, L. Caron, A. Khoshoei, T. Ollevier, Org. Lett., 2022, 24, 2675-2678.

DOI: 10.1021/acs.orglett.2c00762

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Abstract

A Bi(V) compound catalyzes an oxidation of hydrazones into diazo compounds in the presence NaBO₃·H₂O as the terminal oxidant. Ph₃Bi(OAc)₂ as catalyst is in situ generated from BiPh₃ and AcOH. The reaction was applied for the synthesis of diazocarbonyls and 2,2,2-trifluoromethyl diazoalkanes in very good yields.

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General Procedure

To a vial equipped with a magnetic stir bar, Ph₃Bi (5 mol %) and NaBO₃·H₂O (1.1 equiv) were suspended in MeOH (0.8 mL). The hydrazone (1 equiv) was then added, followed by AcOH (3 mL). The reaction was vigorously stirred at room temperature. The progress of the reaction was monitored by TLC. After completion, the reaction was quenched with H₂O (3 mL) and extracted with Et₂O (3 x 5 mL). The organic phase was dried over MgSO₄ and concentrated under reduced pressure. The residue was purified by silica gel flash column chromatography (100:0 - 90:10 Hexanes/EtOAc) to afford the pure product. Proof of purity and identity was obtained by ¹H, ¹³C, and ¹⁹F NMR spectroscopy.

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Key Words

Diazo Compounds, Sodium Perborate

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ID: J54-Y2022