4970-79-0Relevant articles and documents
Optimization of nazarov cyclization of 2,4-dimethyl-1,5-diphenylpenta-1,4-dien-3-one in deep eutectic solvents by a design of experiments approach
Baldino, Salvatore,Blangetti, Marco,Fin, Andrea,Mannu, Alberto,Nejrotti, Stefano,Prandi, Cristina
, (2020/12/29)
The unprecedentedNazarov cyclization of amodel divinyl ketone using phosphonium-based Deep Eutectic Solvents as sustainable non-innocent reactionmedia isdescribed. Atwo-level full factorial Design ofExperimentswas conductedfor elucidating the effect of the components of the eutecticmixture and optimizing the reaction conditions in terms of temperature, time, and substrate concentration. In the presence of the Deep Eutectic Solvent (DES) triphenylmethylphosphonium bromide/ethylene glycol, it was possible to convert more than 80% of the 2,4-dimethyl-1,5-diphenylpenta-1,4-dien-3-one, with a specific conversion, into the cyclopentenone Nazarov derivative of 62% (16 h, 60 °C). For the reactions conducted in the DES triphenylmethylphosphonium bromide/acetic acid, quantitative conversions were obtained with percentages of the Nazarov product above 95% even at 25 °C. Surface Responding Analysis of the optimized data furnished a useful tool to determine the best operating conditions leading to quantitative conversion of the starting material, with complete suppression of undesired side-reactions, high yields and selectivity. After optimization, it was possible to convert more than 90% of the model substrate into the desired cyclopentenone with cis percentages up to 77%. Experimental validation of the implemented model confirmed the robustness and the suitability of the procedure, leading to possible further extension to this specific combination of experimental designs to other substrates or even to other synthetic processes of industrial interest.
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
, 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.
Interrupting Nazarov Reaction with Different Trapping Modality: Utilizing Potassium Alkynyltrifluoroborate as a σ-Nucleophile
William, Ronny,Wang, Siming,Mallick, Asadulla,Liu, Xue-Wei
supporting information, p. 4458 - 4461 (2016/09/28)
The putative oxyallyl cation intermediate generated following Nazarov cyclization of dienone has been successfully intercepted with potassium alkynyltrifluoroborates which act as σ-nucleophiles in the presence of BF3·Et2O. This new t
Synthesis of oxathiane and morpholine from acyclic precursors: A modified Mitsunobu reaction
Paul, Nidhin,Kaladevi, Selvam,Beneto, Arockiam Jesin,Muthusubramanian, Shanmugam,Bhuvanesh, Nattamai
, p. 6892 - 6901 (2012/09/11)
Synthesis of a set of isomeric 2,4,6-triarylmorpholines and 2,6-diaryloxathianes from the corresponding 1,5-diols has been described. The method provides an efficient route to six-membered heterocycles from acyclic diols and is found to be better than Mitsunobu procedure in yield and waste management. In a related study, the ring contraction of pyranone to two isomeric cyclopentenone derivatives through Nazarov reaction has been noticed.
Polymer-mediated reactions. A Nazarov-like cyclization
Pavlik, Christopher,Morton, Martha D.,Invernale, Michael A.,Berghorn, Ian D.,Sotzing, Gregory A.,Smith, Michael B.
supporting information; experimental part, p. 2195 - 2199 (2011/11/06)
The polymer PEDOT+ mediates a Nazarov-like cyclization of dienones, in an heterogeneous system and in hydrocarbon solvents. The polymer-mediated reactions show clear differences in product formation when compared to the same reaction with tosic acid, or when compared to reports in the literature. Comparable or improved yields are observed, as well as the ability to give a -Nazarov product in cases where treatment with acid fails to give cyclization, or leads to an undesirable rearrangement. In addition, the ability to recycle the polymer makes this a potentially useful protocol for an important organic chemical reaction. Georg Thieme Verlag Stuttgart · New York.
