- Highly effective and enantioselective Michael addition of 4-hydroxycoumarin to α,β-unsaturated ketones promoted by simple chiral primary amine thiourea bifunctional catalysts
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Highly asymmetric Michael addition of 4-hydroxycoumarin to α,β-unsaturated ketones promoted by chiral primary amine thiourea bifunctional catalysts was developed and a series of Michael adducts were obtained in excellent yields (up to 97%) and enantioselectivities (up to 95% ee). Optically pure S-warfarin was easily obtained in 99% ee after single recrystallization.
- Mei, Ren-Qiang,Xu, Xiao-Ying,Li, Yan-Chun,Fu, Ji-Ya,Huang, Qing-Chun,Wang, Li-Xin
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supporting information; experimental part
p. 1566 - 1568
(2011/05/05)
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- Highly enantioselective Michael addition of cyclic 1,3-dicarbonyl compounds to α,β-unsaturated ketones
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The highly enantioselective Michael addition of 1,3-cyclic dicarbonyl compounds to α,β-unsaturated ketones was reported to be catalyzed by an organic primary amine derived from quinine. A chiral anticoagulant drug, (S)-warfarin, was directly prepared in 96% ee, and other related important adducts were also obtained in excellent enantioselectivity (89-99% ee).
- Xie, Jian-Wu,Yue, Lei,Chen, Wei,Du, Wei,Zhu, Jin,Deng, Jin-Gen,Chen, Ying-Chun
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p. 413 - 415
(2008/02/12)
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- Organocatalytic Asymmetric Michael Reaction of Cyclic 1,3-Dicarbonyl Compounds and α,β-Unsaturated Ketones - A Highly Atom-Economic Catalytic One-Step Formation of Optically Active Warfarin Anticoagulant
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A broad range of Michael adducts 3 were obtained by the organocatalytic asymmetric Michael addition of cyclic 1,3-dicarbonyl compounds 1 to α,β-unsaturated ketones 2. The reaction allows a one-step synthesis of the optically active anti-coagulant warfarin and several analogues 3 on a kilogram scale in up to 99% yield with 88% ee (>99.9% ee after a single recrystallization).
- Halland, Nis,Hansen, Tore,Jorgensen, Karl Anker
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p. 4955 - 4957
(2007/10/03)
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