Divergent Access to Spirocyclic and Atropisomeric Benzimidazothiazole Derivatives by Halogen‐Promoted Intramolecular Dienamine Sulfenylation

Herein, we report a divergent and efficient strategy for accessing two novel structural families of benzo4,5imidazo2,1‐bthiazoles through halogen‐promoted intramolecular sulfenylation of functionalized dienamines. The method provides precise control over product formation through the geometry ( Z or E ) of the starting material (substrate‐controlled divergence) and the choice of electrophilic halogenating agent, Selectfluor or ICl (reagent‐controlled divergence). The resulting benzimidazothiazole scaffolds display highly appealing stereochemical features: spirolactones bearing a quaternary carbon stereocenter and heteroaryl acrylates incorporating a stereogenic axis. The latter constitute a previously unreported class of atropisomeric alkenes exhibiting remarkable configurational stability. Combined experimental and computational studies revealed rotational barriers above 30 kcal mol −1 , corresponding to calculated half‐lives exceeding 1000 years at room temperature. One atropodiastereomer derived from L ‐menthol was isolated, and its absolute configuration established by single‐crystal X‐ray diffraction. Overall, this work provides a versatile platform for constructing spirocyclic or atropisomeric N , S ‐heterocycles, thereby expanding the accessible chemical space of benzimidazothiazoles with potential pharmaceutical relevance. It also offers new insights into nonbiaryl atropisomerism, particularly within axially chiral aryl–alkenyl frameworks.