Tetrahedron letters

Bifunctional thiourea-catalyzed enantioselective double Michael reaction of γ, δ-unsaturated β-ketoester to nitroalkene: asymmetric synthesis of (−)-epibatidine

Y Hoashi, T Yabuta, Y Takemoto

Index: Hoashi, Yasutaka; Yabuta, Takaya; Takemoto, Yoshiji Tetrahedron Letters, 2004 , vol. 45, # 50 p. 9185 - 9188

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Citation Number: 149

Abstract

The asymmetric synthesis of 4-nitrocyclohexanone derivatives has been accomplished by enantioselective double Michael additions of γ, δ-unsaturated β-ketoesters to nitroalkenes using a catalytic amount of bifunctional thiourea and TMG. The three contiguous stereogenic centers of the obtained products were constructed with good to high diastereoselectivity and up to 92% ee. The biologically active natural product,(−)-epibatidine, has been ...