1, 3-Dipolar cycloaddition of hydrazones with α-oxo-ketenes: a three-component stereoselective entry to pyrazolidinones and an original class of spirooxindoles

M Presset, K Mohanan, M Hamann, Y Coquerel…

Index: Presset, Marc; Mohanan, Kishor; Hamann, Marie; Coquerel, Yoann; Rodriguez, Jean Organic Letters, 2011 , vol. 13, # 15 p. 4124 - 4127

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Citation Number: 39

Abstract

Stereodefined monocyclic, spirobicyclic, and bis-spirotricyclic pyrazolidin-3-ones can be prepared efficiently by a three-component reaction involving a 1, 3-dipolar cycloaddition of azomethine imines obtained from hydrazones with α-oxo-ketene dipolarophiles generated in situ. The reaction allows the creation of four covalent bonds and two contiguous chiral quaternary centers with excellent diastereoselectivity in a single catalyst/additive-free, ...