Synthesis of fully functionalised spiropyran pyrazolone skeletons via a formal [4 + 2] cascade process using β-nitro-styrene-derived MBH-alcohols

An efficient protocol was established to construct spiro pyrazolone tetrahydropyran scaffolds at ambient temperature under metal-free conditions. The reaction proceeded via formal [4 + 2] cyclisation of trans-β-nitro-styrene-derived Morita–Baylis–Hillman (MBH) alcohol with α-arylidene pyrazolone. Th...

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Detalles Bibliográficos
Autores principales: Reddy, Yeruva Pavankumar, Anwar, Shaik
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society of Chemistry 2022
Materias:
Chemistry
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9717676/
https://www.ncbi.nlm.nih.gov/pubmed/36545601
http://dx.doi.org/10.1039/d2ra06076k
Descripción
Sumario:An efficient protocol was established to construct spiro pyrazolone tetrahydropyran scaffolds at ambient temperature under metal-free conditions. The reaction proceeded via formal [4 + 2] cyclisation of trans-β-nitro-styrene-derived Morita–Baylis–Hillman (MBH) alcohol with α-arylidene pyrazolone. The reaction followed an oxa-Michael/Michael cascade pathway, resulting in the formation of new C–C and C–O bonds. Organocatalytic synthesis of spiropyrazolones using quinine-derived catalyst resulted in 94% enantiomeric excess (ee) and excellent (>20 : 1) diastereoselectivity.

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