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[摘要]:The asymmetric domino reaction of various alpha,alpha-dicyano olefins to 3-nitro-2H-chromenes was studied employing readily available cinchona-derived bifunctional thioureas as organocatalysts. These new transformations were highly regio-, chemo-, diastereo-, and enantioselective simultaneously giving chiral multi-functionalized polyheterocyclic benzopyran derivatives with multi-chiral carbon centers. |
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