Synthesis and Claisen Rearrangement of Bridged Bicyclic Enol Ethers of Relevance to the Course of Ketene s-cis-Diene Cycloaddition.

ChemInform ◽  
2007 ◽  
Vol 38 (15) ◽  
Author(s):  
Jeremy Robertson ◽  
Thomas G. Fowler
Keyword(s):  
Claisen Rearrangement ◽  
Enol Ethers

α-Alkoxyalkyl Triphenylphosphonium Salts: Synthesis and Reactions

2019 ◽  
Vol 23 (16) ◽  
pp. 1738-1755
Author(s):  
Humaira Y. Gondal ◽  
Zain M. Cheema ◽  
Abdul R. Raza ◽  
Ahmed Abbaskhan ◽  
M. I. Chaudhary
Keyword(s):  
Carbonyl Compounds ◽  
Claisen Rearrangement ◽  
Alder Reaction ◽  
Coupling Reactions ◽  
Phosphonium Salts ◽  
Organic Transformations ◽  
Enol Ethers ◽  
Wide Range ◽  
Synthetic Methodologies ◽  
Alkoxy Groups

Following numerous applications of Wittig reaction now functionalized phosphonium salts are gaining attention due to their characteristic properties and diverse reactivity. This review is focused on α-alkoxyalkyl triphenylphosphonium salts: an important class of functionalized phosphonium salts. Alkoxymethyltriphenylphosphonium salts are majorly employed in the carbon homologation of carbonyl compounds and preparation of enol ethers. Their methylene insertion strategy is extensively demonstrated in the total synthesis of a wide range of natural products and other important organic molecules. Similarly enol ethers prepared thereof are important precursors for different organic transformations like Diels-Alder reaction, Claisen rearrangement, Coupling reactions, Olefin metathesis and Nazarov cyclization. Reactivity of these α-alkoxyalkylphosphonium salts have also been studied in the nucleophilic substitution reactions. A distinctive application of this class of phosphonium salts was recently reported in the phenylation of carbonyl compounds under very mild conditions. Synthesis of structurally diverse alkoxymethyltriphenylphosphonium salts with variation in alkoxy groups as well as counter anions are reported in literature. Here we present a detailed account of different synthetic methodologies for the preparation of this unique class of quaternary phosphonium salts and their applications in organic synthesis.

Diastereocontrol via the phenol- and palladium(II)-catalyzed Claisen rearrangement with cyclic enol ethers

1987 ◽  
Vol 28 (47) ◽  
pp. 5879-5882 ◽  
Author(s):  
Kōichi Mikami ◽  
Kazuhiko Takahashi ◽  
Takeshi Nakai
Keyword(s):  
Claisen Rearrangement ◽  
Enol Ethers

Synthesis and Claisen rearrangement of alkoxyallyl enol ethers. Evidence for a dipolar transition state

1987 ◽  
Vol 109 (4) ◽  
pp. 1160-1170 ◽  
Author(s):  
Robert M. Coates ◽  
Brian D. Rogers ◽  
Steven J. Hobbs ◽  
Dennis P. Curran ◽  
David R. Peck
Keyword(s):  
Transition State ◽  
Claisen Rearrangement ◽  
Enol Ethers

ChemInform Abstract: Synthesis and Claisen Rearrangement of Alkoxyallyl Enol Ethers. Evidence for a Dipolar Transition State.

ChemInform ◽  
1987 ◽  
Vol 18 (26) ◽  
Author(s):  
R. M. COATES ◽  
B. D. ROGERS ◽  
S. J. HOBBS ◽  
D. R. PECK ◽  
D. P. CURRAN
Keyword(s):  
Transition State ◽  
Claisen Rearrangement ◽  
Enol Ethers

scholarly journals Global Diastereoconvergence in the Ireland–Claisen Rearrangement of Isomeric Enolates: Synthesis of Tetrasubstituted -Amino Acids

2020 ◽  
Author(s):  
Tyler J. Fulton ◽  
Alexander Cusumano ◽  
Eric J. Alexy ◽  
Yun Emily Du ◽  
Haiming Zhang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Theoretical Investigation ◽  
Claisen Rearrangement ◽  
State Of The Art ◽  
Coupled Cluster ◽  
Quantum Mechanical ◽  
Density Func Tional Theory ◽  
Coupled Cluster Theory ◽  
Enol Ethers ◽  
Allyl Esters

<div><div><div><p>A dual experimental/theoretical investigation of the Ireland–Claisen rearrangement of tetrasubstituted a-phthalimido ester enolates to afford a-tetrasubstituted, b-trisubstituted a-amino acids (generally >20:1 dr) is described. For trans allylic olefins, the Z and E-enol ethers proceed through chair and boat transition states, respectively. For cis allylic olefins, the trend is reversed. As a result, the diastereochemical outcome of the reaction is preserved regardless of the geometry of the enolate or the accompanying allylic olefin. We term this unique convergence of all possible olefin isomers as global diastereoconvergence. This reaction manifold circumvents limitations in present-day technologies for the stereoselective enolization of a,a-disubstituted allyl esters. Density func- tional theory paired with state-of-the-art local coupled-cluster theory (DLPNO-CCSD(T)) was employed for the accurate determina- tion of quantum mechanical energies.</p></div></div></div>

scholarly journals Direct C–H Alpha Arylation of Enones with ArI(O2CR)2 Reagents

2019 ◽  
Author(s):  
Felipe Cesar Sousa e Silva ◽  
Nguyen T Van ◽  
Sarah Wengryniuk
Keyword(s):  
Claisen Rearrangement ◽  
Bond Formation ◽  
Hypervalent Iodine ◽  
Enol Ethers ◽  
Silyl Enol Ethers ◽  
Metal Free ◽  
Wide Range ◽  
Reaction Proceeds ◽  
Mechanistic Investigations

Herein, we report the metal-free direct C–H arylation of enones mediated by hypervalent iodine reagents. The reaction proceeds via a reductive iodonium Claisen rearrangement of <i>in situ </i>b-pyridinium silyl enol ethers. The aryl groups are derived from ArI(O<sub>2</sub>CCF<sub>3</sub>)<sub>2</sub> reagents, which are readily accessed from the parent iodoarenes. It is tolerant of a wide range of substitution patterns and the incorporated arenes maintain the valuable iodine functional handle. Mechanistic investigations implicate arylation via an umpoled “enolonium” species and that the presence of a b-pyridinium moiety is critical for desired C–C bond formation.

Claisen rearrangement of α-(F-alkyl)enol ethers prepared via Wittig olefination of allyl perfluoroalkanoates

1994 ◽  
Vol 35 (18) ◽  
pp. 2907-2910 ◽  
Author(s):  
Jean-Pierre Bégué ◽  
Danièle Bonnet-Delpon ◽  
Shen-Weng Wu ◽  
Abderrahim M'Bida ◽  
Toshiro Shintani ◽  
...  
Keyword(s):  
Claisen Rearrangement ◽  
Enol Ethers ◽  
Wittig Olefination ◽  
Alkyl Enol Ethers

scholarly journals Direct C–H Alpha Arylation of Enones with ArI(O2CR)2 Reagents

2019 ◽  
Author(s):  
Felipe Cesar Sousa e Silva ◽  
Nguyen T Van ◽  
Sarah Wengryniuk
Keyword(s):  
Claisen Rearrangement ◽  
Bond Formation ◽  
Hypervalent Iodine ◽  
Enol Ethers ◽  
Silyl Enol Ethers ◽  
Metal Free ◽  
Wide Range ◽  
Reaction Proceeds ◽  
Mechanistic Investigations

Herein, we report the metal-free direct C–H arylation of enones mediated by hypervalent iodine reagents. The reaction proceeds via a reductive iodonium Claisen rearrangement of <i>in situ </i>b-pyridinium silyl enol ethers. The aryl groups are derived from ArI(O<sub>2</sub>CCF<sub>3</sub>)<sub>2</sub> reagents, which are readily accessed from the parent iodoarenes. It is tolerant of a wide range of substitution patterns and the incorporated arenes maintain the valuable iodine functional handle. Mechanistic investigations implicate arylation via an umpoled “enolonium” species and that the presence of a b-pyridinium moiety is critical for desired C–C bond formation.

scholarly journals Global Diastereoconvergence in the Ireland–Claisen Rearrangement of Isomeric Enolates: Synthesis of Tetrasubstituted -Amino Acids

2020 ◽  
Author(s):  
Tyler J. Fulton ◽  
Alexander Cusumano ◽  
Eric J. Alexy ◽  
Yun Emily Du ◽  
Haiming Zhang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Theoretical Investigation ◽  
Claisen Rearrangement ◽  
State Of The Art ◽  
Coupled Cluster ◽  
Quantum Mechanical ◽  
Density Func Tional Theory ◽  
Coupled Cluster Theory ◽  
Enol Ethers ◽  
Allyl Esters

<div><div><div><p>A dual experimental/theoretical investigation of the Ireland–Claisen rearrangement of tetrasubstituted a-phthalimido ester enolates to afford a-tetrasubstituted, b-trisubstituted a-amino acids (generally >20:1 dr) is described. For trans allylic olefins, the Z and E-enol ethers proceed through chair and boat transition states, respectively. For cis allylic olefins, the trend is reversed. As a result, the diastereochemical outcome of the reaction is preserved regardless of the geometry of the enolate or the accompanying allylic olefin. We term this unique convergence of all possible olefin isomers as global diastereoconvergence. This reaction manifold circumvents limitations in present-day technologies for the stereoselective enolization of a,a-disubstituted allyl esters. Density func- tional theory paired with state-of-the-art local coupled-cluster theory (DLPNO-CCSD(T)) was employed for the accurate determina- tion of quantum mechanical energies.</p></div></div></div>

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