| Popis: |
Based on the intramolecular E1cB elimination, a novel [4 + 2] cyclization was designed and successfully applied to the asymmetric synthesis of polycyclic compounds which contained both chromane and spirooxindole moieties. In the reaction, regardless of the competitive pathways resulting from multireactive sites of starting materials, products could be obtained in good yields (up to 84%) and with excellent enantioselectivities (most 98 to99% ee) under the catalysis of a chiral bifunctional thiourea-tertiary amine (1-5 mol %). |
