7169-34-8Relevant articles and documents
A Hg(OTf)2-Catalyzed Enolate Umpolung Reaction Enables the Synthesis of Coumaran-3-ones and Indolin-3-ones
Dai, Ning,Hu, Weican,Qian, Guoying,Rong, Zhouting
supporting information, p. 3286 - 3290 (2020/04/21)
The potential of mercury catalysis has been extended to the arena of enolate umpolung reactions for the first time by the generation of enolonium species via Hg(OTf)2-catalyzed N-oxide addition to alkynes. The enolonium species formed can undergo intramolecular nucleophilic attack by hydroxyl or amino groups, leading to the synthesis of various coumaran-3-ones and indolin-3-ones.
Earth-Abundant Mixed-Metal Catalysts for Hydrocarbon Oxygenation
Pankhurst, James R.,Curcio, Massimiliano,Sproules, Stephen,Lloyd-Jones, Guy C.,Love, Jason B.
supporting information, p. 5915 - 5928 (2018/05/28)
The oxygenation of aliphatic and aromatic hydrocarbons using earth-abundant Fe and Cu catalysts and "green" oxidants such as hydrogen peroxide is becoming increasingly important to atom-economical chemical processing. In light of this, we describe that dinuclear CuII complexes of pyrrolic Schiff-base macrocycles, in combination with ferric chloride (FeCl3), catalyze the oxygenation of π-activated benzylic substrates with hydroperoxide oxidants at room temperature and low loadings, representing a novel design in oxidation catalysis. Mass spectrometry and extended X-ray absorption fine structure analysis indicate that a cooperative action between CuII and FeIII occurs, most likely because of the interaction of FeCl3 or FeCl4- with the dinuclear CuII macrocycle. Voltammetric measurements highlight a modulation of both CuII and FeIII redox potentials in this adduct, but electron paramagnetic resonance spectroscopy indicates that any Cu-Fe intermetallic interaction is weak. High ketone/alcohol product ratios, a small reaction constant (Hammett analysis), and small kinetic isotope effect for H-atom abstraction point toward a free-radical reaction. However, the lack of reactivity with cyclohexane, oxidation of 9,10-dihydroanthracene, oxygenation by the hydroperoxide MPPH (radical mechanistic probe), and oxygenation in dinitrogen-purge experiments indicate a metal-based reaction. Through detailed reaction monitoring and associated kinetic modeling, a network of oxidation pathways is proposed that includes "well-disguised" radical chemistry via the formation of metal-associated radical intermediates.
Synthesis and cyclization of 1-(2-hydroxyphenyl)-2-propen-1-one epoxides: 3-Hydroxychromanones and -flavanones versus 2-(1-hydroxyalkyl)-3-coumaranones
Patonay, Tamas,Levai, Albert,Nemes, Csaba,Timar, Tibor,Toth, Gabor,Adam, Waldemar
, p. 5375 - 5383 (2007/10/03)
Competitive α and β cyclization of 2'-hydroxychalcone epoxides affords 2-(α-hydroxybenzyl)-3-coumaranone and/or 3-hydroxyflavanones, which depends on the conditions employed. Epoxidation of 2'-hydroxychalcones by dimethyldioxirane followed by either base- or acid-catalyzed ring closure provides a novel, general, and efficient method for the synthesis of trans-3-hydroxyflavanones, which includes also the naturally occurring derivatives. Extension of this two-step procedure to 1-(2-hydroxyphenyl)-2-alken-1-ones was also accomplished. A strong preference for α cyclization was observed in the case of β-unsubstituted or -monoalkylated α,β-enones, while both 2,2-dimethyl-3-hydroxychromanones and 2-(1-hydroxy-1-methylethyl)-3-coumaranones were obtained from the β,β-dimethylated substrates.
