Asymmetric [3+2] Annulations of Thioaurone and Aurone Derivatives for the Construction of Spiroheterocycles

摘要

Aurones and their analogues are convenient two-atom units for the rapid construction of valuable spiroheterocycles. Here, we demonstrate that the Morita-Baylis-Hillman carbonates of isatins can be efficiently assembled with thioaurones, aurones, or even methyleneindolinones in a highly asymmetric [3+2] annulation manner, affording a broad spectrum of densely functionalized spiro-benzothiophene, -benzofuran and bisspirooxindole frameworks in high yields with good to excellent stereoselectivity.