Remote Control of Axial Chirality: Synthesis of Spirooxindole-Urazoles via Desymmetrization of ATAD

For the first time, a desymmetrization strategy empowered the assembly of a class of optically pure spirooxindole-urazoles possessing an N-Ar stereogenic axis via remote control of axial chirality in an asymmetric three-component reaction. This transformation was realized by a tandem bisthiourea-catalyzed asymmetric Diels-Alder reaction and substrate-controlled asymmetric ene reaction. The driving force derived from aromatization and the high reactivity of 4-aryl-1,2,4-triazole-3,5-dione enophiles mediated the occurrence of the successive ene reaction under mild conditions.