A Synthetic Approach to Diverse Indole/Oxindole-Annulated <i>S</i> -Heterocycles

The research for developing efficient and practical strategies to access sulfur-containing medium-sized rings is of great interest, yet remains elusive and challenging. Herein, we describe a versatile strategy enabling the facile construction of indole/oxindole-annulated medium-sized <i>S</i>-heterocycles via rearrangement reactions between diazooxindoles and thiolactones. The presented protocol affords excellent yields with high regio-, chemo-, diastereo-, and enantioselectivity. DFT calculations were conducted to gain a more profound understanding of the reaction mechanism.