Chiral bifunctional squaramide catalyzed asymmetric tandem Michael-cyclization reaction: efficient synthesis of optically active 2-amino-4H-chromene-3-carbonitrile derivatives
writer：Keling Hu, Aidang Lu, Youming Wang, Zhenghong Zhou*, Chuchi Tang
keywords：Chiral Squaramide, Tandem Michael-cyclization, Asymmetric Catalysis
source：期刊
specific source：Tetrahedron Asymmetry
Issue time：2013年
We have developed an efficient bifunctional squaramide catalyst for the asymmetric tandem Michael addition–cyclization of malononitrile to functionalized nitroolefins. This organocatalytic asymmetric reaction provides convenient and valuable access to highly functionalized 2-amino-4H-chromene derivatives, which possess important biological activities, in good yields with moderate to high enantioselectivities (up to 95% ee).