Divergent Pathways and Competitive Mechanisms of Metathesis Reactions between 3‐Arylprop‐2‐ynyl Esters and Aldehydes: An Experimental and Theoretical Study

Trujillo, Cristina; Sánchez‐Sanz, Goar; Karpaviciene, Ieva; Jahn, Ullrich; Čikotienė, Inga; Rulı́s̆ek, Lubomı́r

doi:10.1002/chem.201402551

Cited by 15 publications

(3 citation statements)

References 81 publications

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“…In the light of the above results and previous reports,, a tentative mechanism for this transformation is proposed in Scheme . First, a silver‐activated aldehyde intermediate B is formed via a Ag(I)‐catalyzed ring‐opening of epoxides 2 , followed by a subsequent 1,2‐H shift .…”

Section: Screening Of the Reaction Conditions[a]supporting

confidence: 59%

Synthesis of (E)‐α,β‐Unsaturated Carbonyls via Silver‐Catalyzed Tandem Epoxide Rearrangement/Intermolecular Carbonyl‐ Heteroalkyne Metathesis

Zhu

Jin

et al. 2016

Adv Synth Catal

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Ar egio-and stereoselective method for the synthesiso f( E)-a,b-unsaturated carbonyls has been developed via as ilver-catalyzedt andem epoxide rearrangement/intermolecular carbonyl-heteroalkyne metathesis.V arioush eteroalkynes including ynol ethers,y namides,a nd thioalkynes work well for this transformation, leading to the production of (E)-a,b-unsaturated esters,a mides,a nd thioesters in moderate to excellent yields with good functional group compatibility.I tr epresents one of the rare examples of regio-ands tereoselective intermolecular alkyne-carbonyl metathesis(ACM).

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Section: Screening Of the Reaction Conditions[a]supporting

confidence: 59%

Synthesis of (E)‐α,β‐Unsaturated Carbonyls via Silver‐Catalyzed Tandem Epoxide Rearrangement/Intermolecular Carbonyl‐ Heteroalkyne Metathesis

Zhu

Jin

et al. 2016

Adv Synth Catal

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“…All quantum chemical calculations were performed with the Gaussian suite of programs at uωB97XD/6–311++G(2d,2p) level . Since formation of a H

\dots

O hydrogen bond (HB) precedes formation of a HO covalent bond, we employed ωB97XD functional that is able to properly describe both weak and strong interactions . Presence of species with unpaired electrons required employment of unrestricted methods (uωB97XD).…”

Section: Methodsmentioning

confidence: 99%

Mechanistic insights on how hydroquinone disarms OH and OOH radicals

Nakarada

Petković

2017

Int J of Quantum Chemistry

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Phenol derivatives are distinguished as successful free radical scavengers. We present a detailed analysis of hydroxyl hydrogen abstraction from hydroquinone by hydroxyl and hydroperoxyl radical with emphasis on changes that take place in the vicinity of the transition state. Quantum theory of atoms in molecules is employed to elucidate the sequence of positive and negative charge transfer by studying selected properties of the three key atoms (the transferring hydrogen, the donor atom, and the acceptor atom) along intrinsic reaction path. The presented results imply that in both reactions, which are examples of proton coupled electron transfer, proton, and electron get simultaneously transferred to the radical oxygen atom. The fact that the hydrogen's charge and volume do not monotonously change in the vicinity of the transition state in the product valley results from the adjacency of the proton and the electron to the donor and the acceptor oxygen atoms. Obtaining a detailed understanding of mechanisms by which free radicals are disarmed is of paramount importance given the effects of those highly reactive species on biological systems. A comprehensive analysis of hydroxyl hydrogen abstraction from hydroquinone by hydroxyl and hydroperoxyl radicals, based on changes of selected electronic properties of the three most relevant atoms (hydrogen donor, hydrogen acceptor, and the hydrogen itself), along the reaction coordinate, can be obtained by first-principles calculations. K E Y W O R D S density functional theory, free radical scavenging, hydroquinone, proton coupled electron transfer, quantum theory of atoms in molecules 1 | I N TR ODU C TI ONDue to their ability to cause oxidative stress in living organisms, free radicals are held responsible for aging process. Although certain natural products have antioxidative properties, scientists still search for efficient tools to trap those extremely reactive species. Phenol derivatives are wellknown antioxidants [1,2] that terminate radical chain reactions by donating a hydroxyl hydrogen atom. Hydrogen atom could also be abstracted from either of phenolic CAH bonds, although such processes are characterized with higher energy barrier due to lower acidity of the transferring atom.In addition to hydrogen transfer, free radicals can be blocked through formation of an adduct with the scavenger.Hydrogen transfer can, in principle, proceed via several reaction mechanisms [3][4][5][6] due to the fact that hydrogen atom consists of two entities-a proton and an electron. They can be transferred either simultaneously or separately, and the process might also involve solvent molecules. All those mechanisms are known as formal hydrogen transfer (FHT). [6] (i) If hydrogen transfer takes place in a single elementary step, it can be either hydrogen atom transfer (HAT) when the proton and the electron are transferred from one species to another as one entity, or proton-coupled electron transfer (PCET) if the proton and the electron travel separately between different parts of molec...

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“…Depending on the structure of the starting materials and the reaction conditions, the products of these reactions can be Morita-Baylis-Hillman (MBH) adducts that are unavailable by traditional MBH reactions or E-and Z-enones. 3 Mechanistic studies of these reactions were performed by isotopic labeling experiments.…”

Section: Guizhou Yue Was Born In Hubei (P R Of Chinamentioning

confidence: 99%

Synform Issue 2015/12

Zanda¹

2015

Synthesis

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Literature Coverage Synform tetraol in a single pot through thoughtful selection of the protecting and reducing silanes," said Professor Dabrowski. Professor Gagné concluded: "Whilst some of the products formed by this method are established fine chemicals, the majority of them are undisclosed and therefore offer the poten tial for new applications. Furthermore, the developed method ology opens new avenues of research to convert biomass into fine chemicals as the field of sustainable chemistry continues to expand." A171 Scheme 3 Divergent reduction of dehydrated glucose and mannose Laura L. Adduci graduated from Brandeis University in Waltham, MA (USA) in 2009 with a B.S. in chemistry. She then began graduate studies in chemistry under the direction of Professor Michel R. Gagné at the University of North Carolina at Chapel Hill (USA), where she focused on selective carbohydrate transformations. Upon completion of her Ph.D., she accepted a position at Eastman Chemical Company in Kingsport, TN (USA). Her main interests involve characterization of small molecules and polymers. Literature Coverage Synform A173 Scheme Plausible mechanism for a combined photoredox and asymmetric catalysis with a chiral iridium Lewis acid photoredox sensitizer; light source: 20 W compact fluorescent lamp (CFL)

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Divergent Pathways and Competitive Mechanisms of Metathesis Reactions between 3‐Arylprop‐2‐ynyl Esters and Aldehydes: An Experimental and Theoretical Study

Cited by 15 publications

References 81 publications

Synthesis of (E)‐α,β‐Unsaturated Carbonyls via Silver‐Catalyzed Tandem Epoxide Rearrangement/Intermolecular Carbonyl‐ Heteroalkyne Metathesis

Synthesis of (E)‐α,β‐Unsaturated Carbonyls via Silver‐Catalyzed Tandem Epoxide Rearrangement/Intermolecular Carbonyl‐ Heteroalkyne Metathesis

Mechanistic insights on how hydroquinone disarms OH and OOH radicals

Synform Issue 2015/12

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