1218940-58-9Relevant academic research and scientific papers
Iodine-Catalyzed Nazarov Cyclizations
Koenig, Jonas J.,Arndt, Thiemo,Gildemeister, Nora,Neud?rfl, J?rg-M.,Breugst, Martin
, p. 7587 - 7605 (2019/06/27)
The Nazarov cyclization is an important pericyclic reaction that allows the synthesis of substituted cyclopentenones. We now demonstrate that this reaction can be performed under very mild, metal-free reaction conditions using molecular iodine as the catalyst. A variety of different divinyl ketones including aromatic systems undergo the iodine-catalyzed reaction with moderate to very good yields in both polar and apolar solvents. Our mechanistic studies indicate that the Nazarov system is activated through a halogen bond between the carbonyl group and the catalyst, and other modes of action like Br?nsted acid or iodonium ion catalysis are unlikely. Furthermore, addition of iodine to the double bond or a putative iodine-catalyzed cis-trans isomerization of the employed olefins seem not to be an important side reaction here.
The first calcium-catalysed Nazarov cyclisation
Davies, Jacob,Leonori, Daniele
, p. 15171 - 15174 (2014/12/11)
The first calcium-catalysed Nazarov cyclisation is described. The Ca(NTf2)(PF6) complex is found to be a very active catalyst for 4π electrocyclisations. The remarkable catalytic activity of this complex is attributed to its increased Lewis acidity compared to other Ca complexes. Spectroscopic studies have provided an insight into the chelating interactions between the substrate and the Ca catalyst.
