American Chemical Society
ol6b03823_si_002.cif (21.95 kB)

Organocatalytic Asymmetric Michael/Hemiketalization/Retro-aldol Reaction of α‑Nitroketones with Unsaturated Pyrazolones: Synthesis of 3‑Acyloxy Pyrazoles

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posted on 2017-01-25, 18:23 authored by Rajendra Maity, Chandan Gharui, Arun K. Sil, Subhas Chandra Pan
An organocatalytic asymmetric cascade Michael/hemiketalization/retro-aldol reaction between unsaturated pyrazolones and α-nitroketones is described. A bifunctional thiourea catalyst was found to be efficient for this reaction. With 10 mol % of catalyst, high yields as well as excellent enantioselectivities are attained for a variety of 3-acyloxy pyrazoles under mild reaction conditions.