Dinuclear Zinc-Catalyzed Asymmetric Synthesis Of Spirooxindoles And Spiroisochromanones

In 2000,Trost's group designed and synthesized the chiral semi-aza-crown ligand,and widely applied it to a lot of asymmetric catalytic reactions,such as asymmetric aldol reactions,asymmetric Mannich reaction and asymmetric Michael addition reaction,et al.In past two decades,several groups also designed different types of chiral semi-aza-crown ligands.Therefore,we designed and synthesized the novel C1-symmetric chiral semi-aza-crown ligands,and applied to asymmetric tandem reactions of ?-hydroxy/amino carbonyl compounds with different ?,?-unsaturated carbonyl compounds,for the synthesis of the spirooxindoles and spiro spiroisochromanones.The detailed results are summarized as follows:1.Dinuclear zinc-catalyzed the asymmetric synthesis of spirocyclic indanone-isochromanonesThe asymmetric cascade Michael/transesterification reaction of ?-hydroxy indanones with ortho-ester chalcones was realized by using dinuclear zinc catalysts,which afforded an array of the spiroisochromanones bearing the indanone sketelon with excellent yields(up to 92%)and outstanding diastereoselectivities and enantioselectivities(up to > 99:1 and 99% ee).It is the first application of dinuclear zinc catalysts on the asymmetric synthesis of the spiro isochromanones derivates.2.Dinuclear zinc-catalyzed the asymmetric synthesis of spirotetrahydrofuryl oxindolesThe asymmetric cascade Michael/hemiketalization reactions of 3-hydroxy oxindole and ?,?-unsaturated ?-keto esters was realized by using dinuclear zinc catalysts under mild conditions,which provided a series of spriooxindoles derivates containing tetrahydrofuryl skeketon.3.Reaction of ortho-diol as a nucleophile catalyzed by dinuclear zinc-catalystOrtho-diol was successfully activated by the dinuclear zinc catalyst that made it a carbon nucleophile for the Michael addition reaction.This is the first experimental study of carbon atoms of ortho-diol as nucleophile sites.Under mild conditions,the asymmetric cascade reaction between N-p-toluene sulfonyl-2,3-dihydroxy dihydroindoles and ?,?-unsaturated ?-keto esters was carried out successfully,and a series of multi-substituted chiral tetrahydrofuran compounds were obtained with good to excellent enantioselectivity.4.Dinuclear zinc-catalyzed the asymmetric synthesis of 2,5-pyrrolidinyl dispirooxindolesThrough the dinuclear zinc catalyst,we realized the asymmetric cascade Michael/cyclic keto-imine formation/Friedel-Crafts reacions of 3-amino oxindoles and ?,?-unsaturated ?-keto amides,which afforded a diversity of 2,5-pyrrolidinyl dispirooxindoles derivates bearing two spiro-quaternary stereocenters.In particularly,one of the spirooxindole skeleton was constructed through Friedel-Crafts reaction,which was important in the organic synthesis.