649570-34-3Relevant academic research and scientific papers
Natural deep eutectic solvents as an efficient and reusable active system for the Nazarov cyclization
Nejrotti, Stefano,Iannicelli, Marta,Jamil, Salwa Simona,Arnodo, Davide,Blangetti, Marco,Prandi, Cristina
supporting information, p. 110 - 117 (2020/01/13)
Natural deep eutectic solvents have emerged as alternative non-toxic, non-aqueous solvents for an increasing number of synthetic transformations. Remarkably, in some cases one (or more) components of the NaDES plays an active role in the reaction mechanism and directly participates as either a catalyst or a reagent in the reaction. In this paper, we tested several NaDESs in which one of the components is a carboxylic acid as a medium to perform the Nazarov cyclization of divinyl ketones to obtain cyclopentenones, a widespread motif in natural compounds. The reaction conditions were optimized and the scope was investigated on C-, O- A nd N-derived compounds. To assess the full sustainability of the proposed approach, the recyclability and scalability of the process were investigated, thus proving that multi-gram preparations are possible with complete recycling of the medium.
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.
Efficient Nazarov Cyclizations of 2-Alkoxy-1,4-pentadien-3-ones
Liang, Guangxin,Gradl, Stefan N.,Trauner, Dirk
, p. 4931 - 4934 (2007/10/03)
(Equation presented) Expeditious and high-yielding Nazarov cyclizations of 2-alkoxy-1,4-pentadien-3-ones are described. An example of a catalytic asymmetric Nazarov cyclization is presented.
