Phosphine‐Catalyzed Double Aza‐Addition of Cyclohexadienone‐Tethered Alkynoates

Alkynes present unique activation challenges versus allenes and alkenes. Herein, we report a PPh 3 ‐catalyzed double aza‐addition of cyclohexadienone‐tethered alkynoates with sulfonamides to construct densely functionalized cis ‐hydrobenzomorpholines through sequential α‐umpolung addition/Michael addition process. Sulfonamides serve as formal N 1 ‐synthons in this modular [5+1] annulation, delivering products with high yields (up to 93%) and diastereoselectivity (generally > 10:1 Z : E ). The method accommodates diverse substrates, including drug motifs, enabling late‐stage diversification of sulfonamide pharmaceuticals through a single operation.