Synergistic Steric Effects in the Development of a Palladium‐Catalyzed Alkyne Carbohalogenation: Stereodivergent Synthesis of Vinyl Halides. (6th November 2014)

• Record Type: Journal Article
• Authors: Le, Christine M.; Menzies, Perry J. C.; Petrone, David A.; Lautens, Mark
• Is Part Of: Angewandte Chemie. Volume 127:Number 1(2015)
• Page Start: 256
• Page End: 259
• Publication Date: 2014-11-06
• Subjects: Carbohalogenierung -- Cyclisierungen -- Palladium -- Reversible oxidative Addition; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201409248
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: We report our finding that by exploiting the synergistic steric effects between substrate and catalyst, an intramolecular Pd‐catalyzed alkyne carbohalogenation can be achieved. This operationally simple method uses the bulky Pd/Q‐Phos combination and allows access to tetrasubstituted vinyl halides from the corresponding aryl chlorides, bromides, and iodides. Steric effects in the substrate play a key role by promoting C sp 2 ‐halogen reductive elimination and enabling catalytic turnover. Through a reversible oxidative addition mechanism, a thermodynamically driven isomerization reaction is observed at elevated temperatures. Thus by changing the reaction temperature, both stereoisomers of the reaction become readily accessible. Abstract : Eine Frage der Sterik : Eine intramolekulare Pd‐katalysierte Alkincarbohalogenierung wurde realisiert, indem die synergistischen sterischen Effekte zwischen Substrat und Katalysator genutzt wurden. Die Reaktion ermöglicht den Zugang zu vierfach substituierten Vinylhalogeniden aus den entsprechenden Arylhalogenverbindungen.