Enantioselective Brønsted Acid-Catalyzed N-Acyliminium Cyclization Cascades

Autor: R. Ian Storer, Graham Trevitt, Adam W. Pilling, Darren J. Dixon, Michael E. Muratore, Chloe A. Holloway
Rok vydání: 2009
Předmět:
Zdroj: Journal of the American Chemical Society. 131:10796-10797
ISSN: 1520-5126
0002-7863
Popis: An enantioselective Brønsted acid-catalyzed N-acyliminium cyclization cascade of tryptamines with enol lactones to form architecturally complex heterocycles in high enantiomeric excess has been developed. The reaction is technically simple to perform as well as atom-efficient and may be coupled to a gold(I)-catalyzed cycloisomerization of alkynoic acids whereby the key enol lactone reaction partner is generated in situ. Employing up to 10 mol % bulky chiral phosphoric acid catalysts in boiling toluene allowed the product materials to be generated in good overall yields (63-99%) and high enantioselectivities (72-99% ee). With doubly substituted enol lactones, high diastereo- and enantioselectivities were obtained, thus providing a new example of a dynamic kinetic asymmetric cyclization reaction.
Databáze: OpenAIRE