Organocatalytic\nDesymmetric Spirocyclization of Enone-Tethered\n2,5-Cyclohexadienone with Isoxazolines to Access Enantioenriched Spiro-Fused\nScaffolds

Enantioselective desymmetric spirocyclization\nis a powerful\ntool\nfor concisely generating intricate 3D molecular architectures from\nreadily accessible substrates. Herein, we report an organocatalytic\ndesymmetric spirocyclization of enone-tethered 2,5-cyclohexadienone\nwith 3-arylisoxazol-5(4<i>H</i>)-one to access enantioenriched\nspiro-fused scaffolds featuring four consecutive stereogenic centers\nin high yields and excellent diastereo- and enantioselectivities.\nThis protocol could proceed smoothly under parts per million-level\norganocatalyst loading. Furthermore, the reusability of the catalyst\nand various intriguing derivatizations of the title product highlight\nits synthetic utility.