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Diastereodivergent asymmetric Michael-alkylation reactions using chiral N,N′-dioxide/metal complexes

A diastereodivergent asymmetric Michael-alkylation reaction between 3-chloro-oxindoles and β,γ-unsaturated-α-ketoesters has been achieved using L-RaPr(2)/Sc(OTf)(3) and L-PrPr(2)/Mg(OTf)(2) metal complexes as catalysts. Both rel-(1R,2S,3R) and rel-(1S,2S,3R) chiral spiro cyclopropane oxindoles were...

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Detalles Bibliográficos
Autores principales: Kuang, Yulong, Shen, Bin, Dai, Li, Yao, Qian, Liu, Xiaohua, Lin, Lili, Feng, Xiaoming
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Royal Society of Chemistry 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5869575/
https://www.ncbi.nlm.nih.gov/pubmed/29629137
http://dx.doi.org/10.1039/c7sc02757e
Descripción
Sumario:A diastereodivergent asymmetric Michael-alkylation reaction between 3-chloro-oxindoles and β,γ-unsaturated-α-ketoesters has been achieved using L-RaPr(2)/Sc(OTf)(3) and L-PrPr(2)/Mg(OTf)(2) metal complexes as catalysts. Both rel-(1R,2S,3R) and rel-(1S,2S,3R) chiral spiro cyclopropane oxindoles were constructed in good yields, diastereoselectivities and ee values. The diastereodivergent control may originate from different alkylation pathways after the Michael addition, with either intramolecular trapping of the aza-ortho-xylylene intermediate or direct S(N)2 substitution.