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Synfacts 2006(4): 0352-0352  
DOI: 10.1055/s-2006-932053
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart · New York

Asymmetric Mannich-Type Reaction in Aqueous Media

Contributor(s): Mark Lautens, Y. Eric Fang
T. Hamada, K. Manabe, S. Kobayashi*
University of Tokyo, Japan
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Publikationsdatum:
24. März 2006 (online)

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Significance

An asymmetric Mannich-type reaction of an α-hydrazono ester with silyl enol ethers in aqueous media afforded α-hydrazino esters in excellent enantioselectivity in the presence of a catalytic amount of ZnF2 and a chiral diamine ligand. The reaction proceeded through a dual activation of the electrophile and nucleophile by the Lewis acid Zn(II) and the Lewis base F-, respectively. The reaction is stereospecific since the Z-enol ether produces the syn product, while the E-enol ether produces the anti product.