We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Catalytic Asymmetric Reactions of 4-Substituted Indoles with Nitroethene: A Direct Entry to Ergot Alkaloid Structures.
- Authors
Romanini, Simone; Galletti, Emilio; Caruana, Lorenzo; Mazzanti, Andrea; Himo, Fahmi; Santoro, Stefano; Fochi, Mariafrancesca; Bernardi, Luca
- Abstract
A domino Friedel-Crafts/nitro-Michael reaction between 4-substituted indoles and nitroethene is presented. The reaction is catalyzed by BINOL-derived phosphoric acid catalysts, and delivers the corresponding 3,4-ring-fused indoles with very good results in terms of yields and diastereo- and enantioselectivities. The tricyclic benzo[ cd]indole products bear a nitro group at the right position to serve as precursors of ergot alkaloids, as demonstrated by the formal synthesis of 6,7-secoagroclavine from one of the adducts. DFT calculations suggest that the outcome of the reaction stems from the preferential evolution of a key nitronic acid intermediate through a nucleophilic addition pathway, rather than to the expected 'quenching' through protonation.
- Subjects
INDOLE; NITROETHYLENE; PHOSPHORIC acid; ENANTIOSELECTIVE catalysis; ERGOT alkaloids
- Publication
Chemistry - A European Journal, 2015, Vol 21, Issue 49, p17578
- ISSN
0947-6539
- Publication type
Article
- DOI
10.1002/chem.201502655