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.
Rognan et al. (2026) studied this question.