N-Heterocyclic Carbene-Catalyzed Aza-Benzoin–Michael Addition–Lactamization Cascade Incorporating a Formal [4 + 1] Annulation to Access Tricyclic Indeno[2,1- b ]pyrrole Derivatives
Abstract
In this letter, we disclose a N-heterocyclic carbene (NHC)-catalyzed one-pot cascade annulation that brings together ortho -formyl cinnamates and benzothiazole imines through an umpolung-driven strategy. This reaction proceeds through the NHC-catalyzed aza-benzoin reaction, followed by intramolecular C-Michael addition and γ-lactamization. The presented cascade quickly builds complex multicyclic indanone-fused heterocycles by forming two carbon–carbon bonds and one amide bond, with two five-membered ring-forming events that feature two stereogenic centers in one go. The densely functionalized products containing benzothiazole were generated in good yields under mild reaction conditions with a broad range of substrates.
Fields of Study & Subjects
N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
Catalytic Cross-Coupling Reactions
Catalytic C–H Functionalization Methods
Publication details
- Journal / source
- Organic Letters
- Publisher
- American Chemical Society (ACS)
- Volume
- 28
- Issue
- 16
- Pages
- 5159–5164
- Publication date
- 15 April 2026
- Language
- EN