Modular Synthesis of Pyrazolones Using an Alkene Aminocarbonylation Reaction.

Kaitlyn Lavergne, Amanda Bongers, Lyanne Betit, André M Beauchemin

Organic letters 2015 Jul 17

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A variety of pyrazolones were synthesized from enol ethers and hydrazones using a reaction sequence involving aminocarbonylation of enol ethers followed by nucleophile-induced aromatization of the azomethine imines intermediates. Using bases to catalyze the in situ formation of imino isocyanates allowed alkene aminocarbonylation to proceed under milder conditions with reactive substrates and enabled aminocarbonylation reactions of sensitive enol ethers. Aromatization of the azomethine imines could be induced by reduction using NaBH4, or by addition of NH2OH to afford the parent (β)N-H products.

Citation

Kaitlyn Lavergne, Amanda Bongers, Lyanne Betit, André M Beauchemin. Modular Synthesis of Pyrazolones Using an Alkene Aminocarbonylation Reaction. Organic letters. 2015 Jul 17;17(14):3612-5