Use of Acylhydrazones as Electrophiles in Mannich-Type Reactions, β-Lactam, Pyrazolidinone, and Pyrazolone Synthesis

Shu Kobayashi; Takayuki Furuta; Kasumi Sugita; Hidekazu Oyamada

doi:10.1055/s-1998-1843

Synlett 1998; 1998(9): 1019-1021
DOI: 10.1055/s-1998-1843

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Use of Acylhydrazones as Electrophiles in Mannich-Type Reactions, β-Lactam, Pyrazolidinone, and Pyrazolone Synthesis

Shu Kobayashi^* , Takayuki Furuta, Kasumi Sugita, Hidekazu Oyamada

^*Graduate School of Pharmaceutical Sciences, The University of Tokyo, and CREST, Japan Science and Technology Corporation (JST), Hongo, Bunkyo-ku, Tokyo 113-0033;

Abstract

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In the presence of a catalytic amount of scandium triflate [Sc(OTf)₃], 4-trifluoromethylbenzoylhydrazones reacted with silyl enolates to afford the corresponding adducts, β-N′-acylhydrazinocarbonyl compounds, in high yields. Reductive cleavage of the nitrogen-nitrogen bond of the hydrazino compounds was performed using Raney Ni under H₂ atmosphere, to give β-aminocarbonyl compounds. The two-step process is regarded as a novel Mannich-type reaction using acylhydrazones as electrophiles. Moreover, the hydrazino compounds were also successfully converted to β-lactam, pyrazolidinone, and pyrazolone derivatives.

acylhydrazone - rare earth triflate - Mannich reaction - β-lactam - pyrazolidinone - Lewis acid catalysis

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