Chiral-Zn(NTf sub(2)) sub(2)-Complex -Catalyzed Diastereo- and Enantioselective Direct Conjugate Addition of Arylacetonitriles to Alkylidene Malonates

Chiral N,N'-dioxide/Zn(NTf sub(2) ) sub(2) complexes were demonstrated to be highly effective in the direct asymmetric conjugate addition of arylacetonitriles to alkylidene malonates under mild conditions. A wide range of substrates were tolerated to afford their corresponding products in moder...

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Bibliographic Details
Published in:Chemistry : a European journal 2013-11, Vol.19 (48), p.16424-16430
Main Authors: Yao, Jingjing, Liu, Xiaohua, He, Peng, Zhu, Yin, Lian, Xiangjin, Lin, Lili, Feng, Xiaoming
Format: Article
Language:English
Subjects:
Alkylidene
Asymmetry
Catalysis
Catalysts
Conjugates
Functional groups
Origins
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Summary:Chiral N,N'-dioxide/Zn(NTf sub(2) ) sub(2) complexes were demonstrated to be highly effective in the direct asymmetric conjugate addition of arylacetonitriles to alkylidene malonates under mild conditions. A wide range of substrates were tolerated to afford their corresponding products in moderate-to-good yields with high diastereoselectivities (82:18->99:1 d.r.) and enantioselectivities (81-99% ee). The reactions performed well, owing to the high Lewis acidity of the metal triflimidate and a ligand-acceleration effect. The N,N'-dioxide also benefited the deprotonation process as a Broensted base. The catalytic reaction could be performed on the gram-scale with retention of yield, diastereoselectivity, and enantioselectivity. The products that contained functional groups were ready for further manipulation. In addition, a possible catalytic model was proposed to explain the origin of the asymmetric induction. Direct route: Chiral N,N'-dioxide/Zn(NTf sub(2) ) sub(2) complexes promoted the direct asymmetric conjugate addition of arylacetonitriles to alkylidene malonates under mild conditions in moderate-to-good yields with high diastereo- and enantioselectivities (see scheme).
ISSN:0947-6539
1521-3765
DOI:10.1002/chem.201302122