Spiroannulations\nof\nβ‑Ketothioamides\nwith Bromoenals via Selective <i>C</i>‑Michael Addition\nand <i>S</i>‑Michael Addition-Triggered Cascade Reactions

A spiroannulation\nreaction of β-ketothioamides with aromatic\nβ-bromoenals and aromatic α-bromoenals via selective <i>C</i>-Michael addition and <i>S</i>-Michael addition-triggered\ncascade reactions has been developed. This protocol provides a novel\nand rapid approach for the synthesis of substituted spirothiopyran\nand spirothiophene derivatives under mild conditions with moderate\nto good yields and a broad substrate scope.