The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Alison J. Frontier - One of the best experts on this subject based on the ideXlab platform.
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efficient nazarov cyclization Wagner Meerwein Rearrangement terminated by a cuii promoted oxidation synthesis of 4 alkylidene cyclopentenones
Chemistry: A European Journal, 2013Co-Authors: David Lebœuf, Eric Theiste, Vincent Gandon, Stephanie L. Daifuku, Michael L. Neidig, Alison J. FrontierAbstract:The discovery and elucidation of a novel Nazarov cyclization/Wagner-Meerwein Rearrangement/oxidation sequence is described, which constitutes an efficient strategy for the synthesis of 4-alkylidene cyclopentenones. DFT computations and EPR experiments were conducted to gain further mechanistic insight into the reaction pathways.
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Efficient Nazarov Cyclization/Wagner–Meerwein Rearrangement Terminated by a CuII‐Promoted Oxidation: Synthesis of 4‐Alkylidene Cyclopentenones
Chemistry (Weinheim an der Bergstrasse Germany), 2013Co-Authors: David Lebœuf, Eric Theiste, Vincent Gandon, Stephanie L. Daifuku, Michael L. Neidig, Alison J. FrontierAbstract:The discovery and elucidation of a novel Nazarov cyclization/Wagner-Meerwein Rearrangement/oxidation sequence is described, which constitutes an efficient strategy for the synthesis of 4-alkylidene cyclopentenones. DFT computations and EPR experiments were conducted to gain further mechanistic insight into the reaction pathways.
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Experimental and Theoretical Studies on the Nazarov Cyclization/Wagner–Meerwein Rearrangement Sequence
Journal of the American Chemical Society, 2012Co-Authors: David Lebœuf, Vincent Gandon, Jennifer Ciesielski, Alison J. FrontierAbstract:Highly functionalized cyclopentenones can be generated by a chemoselective copper(II)-mediated Nazarov/Wagner–Meerwein Rearrangement sequence of divinyl ketones. A detailed investigation of this sequence is described including a study of substrate scope and limitations. After the initial 4π electrocyclization, this reaction proceeds via two different sequential [1,2]-shifts, with selectivity that depends upon either migratory ability or the steric bulkiness of the substituents at C1 and C5. This methodology allows the creation of vicinal stereogenic centers, including adjacent quaternary centers. This sequence can also be achieved by using a catalytic amount of copper(II) in combination with NaBAr4f, a weak Lewis acid. During the study of the scope of the reaction, a partial or complete E/Z isomerization of the enone moiety was observed in some cases prior to the cyclization, which resulted in a mixture of diastereomeric products. Use of a Cu(II)-bisoxazoline complex prevented the isomerization, allowing ...
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experimental and theoretical studies on the nazarov cyclization Wagner Meerwein Rearrangement sequence
Journal of the American Chemical Society, 2012Co-Authors: David Lebœuf, Vincent Gandon, Jennifer Ciesielski, Alison J. FrontierAbstract:Highly functionalized cyclopentenones can be generated by a chemoselective copper(II)-mediated Nazarov/Wagner–Meerwein Rearrangement sequence of divinyl ketones. A detailed investigation of this sequence is described including a study of substrate scope and limitations. After the initial 4π electrocyclization, this reaction proceeds via two different sequential [1,2]-shifts, with selectivity that depends upon either migratory ability or the steric bulkiness of the substituents at C1 and C5. This methodology allows the creation of vicinal stereogenic centers, including adjacent quaternary centers. This sequence can also be achieved by using a catalytic amount of copper(II) in combination with NaBAr4f, a weak Lewis acid. During the study of the scope of the reaction, a partial or complete E/Z isomerization of the enone moiety was observed in some cases prior to the cyclization, which resulted in a mixture of diastereomeric products. Use of a Cu(II)-bisoxazoline complex prevented the isomerization, allowing ...
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Using Nazarov Electrocyclization of Stage Chemoselective [1,2]-Migrations: Stereoselective Synthesis of Functionalized Cyclopentenones.
ChemInform, 2012Co-Authors: David Leboeuf, Jie Huang, Vincent Gandon, Alison J. FrontierAbstract:The title process is based on a stereospecific Cu(II)-mediated Nazarov cyclization/Wagner—Meerwein Rearrangement.
Tohru Fukuyama - One of the best experts on this subject based on the ideXlab platform.
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synthesis of cardiopetaline via a Wagner Meerwein Rearrangement without preactivation of the pivotal hydroxy group
Organic Letters, 2017Co-Authors: Yoshitake Nishiyama, Satoshi Yokoshima, Tohru FukuyamaAbstract:A synthesis of cardiopetaline has been accomplished via a Wagner–Meerwein Rearrangement of a diol having the denudatine skeleton. The Wagner–Meerwein Rearrangement could be facilitated simply by heating the diol with p-toluenesulfonic acid in pivalic acid, without preactivating the pivotal hydroxy group. This strategy does not require differentiation of several hydroxy groups in the substrate for the Wagner–Meerwein Rearrangement and could be applied to the synthesis of more highly oxygenated aconitine-type diterpenoid alkaloids.
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Synthesis of Cardiopetaline via a Wagner–Meerwein Rearrangement without Preactivation of the Pivotal Hydroxy Group
Organic letters, 2017Co-Authors: Yoshitake Nishiyama, Satoshi Yokoshima, Tohru FukuyamaAbstract:A synthesis of cardiopetaline has been accomplished via a Wagner–Meerwein Rearrangement of a diol having the denudatine skeleton. The Wagner–Meerwein Rearrangement could be facilitated simply by heating the diol with p-toluenesulfonic acid in pivalic acid, without preactivating the pivotal hydroxy group. This strategy does not require differentiation of several hydroxy groups in the substrate for the Wagner–Meerwein Rearrangement and could be applied to the synthesis of more highly oxygenated aconitine-type diterpenoid alkaloids.
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Synthesis of Cardiopetaline via a Wagner–Meerwein Rearrangement without Preactivation of the Pivotal Hydroxy Group
2017Co-Authors: Yoshitake Nishiyama, Satoshi Yokoshima, Tohru FukuyamaAbstract:A synthesis of cardiopetaline has been accomplished via a Wagner–Meerwein Rearrangement of a diol having the denudatine skeleton. The Wagner–Meerwein Rearrangement could be facilitated simply by heating the diol with p-toluenesulfonic acid in pivalic acid, without preactivating the pivotal hydroxy group. This strategy does not require differentiation of several hydroxy groups in the substrate for the Wagner–Meerwein Rearrangement and could be applied to the synthesis of more highly oxygenated aconitine-type diterpenoid alkaloids
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Total Synthesis of (−)-Cardiopetaline
Organic letters, 2016Co-Authors: Yoshitake Nishiyama, Satoshi Yokoshima, Tohru FukuyamaAbstract:The total synthesis of (−)-cardiopetaline, an aconitine-type natural product, has been accomplished. Our synthesis involved a Wagner–Meerwein Rearrangement of a sulfonyloxirane that enabled, in a single step, the construction of the bicyclo[3.2.1] system in the aconitine skeleton and effective introduction of oxygen functional groups at the appropriate positions.
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Total synthesis of (-)-isoschizogamine.
Journal of the American Chemical Society, 2012Co-Authors: Yusuke Miura, Satoshi Yokoshima, Noriyuki Hayashi, Tohru FukuyamaAbstract:A first asymmetric total synthesis of (−)-isoschizogamine has been accomplished. Our synthesis features the facile construction of the carbon framework of the natural product through a Wagner–Meerwein Rearrangement, a tandem metathesis, a stereoselective rhodium-mediated 1,4-addition of an arylboronic acid, and a ring-closing metathesis via a hemiaminal ether.
David Lebœuf - One of the best experts on this subject based on the ideXlab platform.
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efficient nazarov cyclization Wagner Meerwein Rearrangement terminated by a cuii promoted oxidation synthesis of 4 alkylidene cyclopentenones
Chemistry: A European Journal, 2013Co-Authors: David Lebœuf, Eric Theiste, Vincent Gandon, Stephanie L. Daifuku, Michael L. Neidig, Alison J. FrontierAbstract:The discovery and elucidation of a novel Nazarov cyclization/Wagner-Meerwein Rearrangement/oxidation sequence is described, which constitutes an efficient strategy for the synthesis of 4-alkylidene cyclopentenones. DFT computations and EPR experiments were conducted to gain further mechanistic insight into the reaction pathways.
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Efficient Nazarov Cyclization/Wagner–Meerwein Rearrangement Terminated by a CuII‐Promoted Oxidation: Synthesis of 4‐Alkylidene Cyclopentenones
Chemistry (Weinheim an der Bergstrasse Germany), 2013Co-Authors: David Lebœuf, Eric Theiste, Vincent Gandon, Stephanie L. Daifuku, Michael L. Neidig, Alison J. FrontierAbstract:The discovery and elucidation of a novel Nazarov cyclization/Wagner-Meerwein Rearrangement/oxidation sequence is described, which constitutes an efficient strategy for the synthesis of 4-alkylidene cyclopentenones. DFT computations and EPR experiments were conducted to gain further mechanistic insight into the reaction pathways.
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Experimental and Theoretical Studies on the Nazarov Cyclization/Wagner–Meerwein Rearrangement Sequence
Journal of the American Chemical Society, 2012Co-Authors: David Lebœuf, Vincent Gandon, Jennifer Ciesielski, Alison J. FrontierAbstract:Highly functionalized cyclopentenones can be generated by a chemoselective copper(II)-mediated Nazarov/Wagner–Meerwein Rearrangement sequence of divinyl ketones. A detailed investigation of this sequence is described including a study of substrate scope and limitations. After the initial 4π electrocyclization, this reaction proceeds via two different sequential [1,2]-shifts, with selectivity that depends upon either migratory ability or the steric bulkiness of the substituents at C1 and C5. This methodology allows the creation of vicinal stereogenic centers, including adjacent quaternary centers. This sequence can also be achieved by using a catalytic amount of copper(II) in combination with NaBAr4f, a weak Lewis acid. During the study of the scope of the reaction, a partial or complete E/Z isomerization of the enone moiety was observed in some cases prior to the cyclization, which resulted in a mixture of diastereomeric products. Use of a Cu(II)-bisoxazoline complex prevented the isomerization, allowing ...
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experimental and theoretical studies on the nazarov cyclization Wagner Meerwein Rearrangement sequence
Journal of the American Chemical Society, 2012Co-Authors: David Lebœuf, Vincent Gandon, Jennifer Ciesielski, Alison J. FrontierAbstract:Highly functionalized cyclopentenones can be generated by a chemoselective copper(II)-mediated Nazarov/Wagner–Meerwein Rearrangement sequence of divinyl ketones. A detailed investigation of this sequence is described including a study of substrate scope and limitations. After the initial 4π electrocyclization, this reaction proceeds via two different sequential [1,2]-shifts, with selectivity that depends upon either migratory ability or the steric bulkiness of the substituents at C1 and C5. This methodology allows the creation of vicinal stereogenic centers, including adjacent quaternary centers. This sequence can also be achieved by using a catalytic amount of copper(II) in combination with NaBAr4f, a weak Lewis acid. During the study of the scope of the reaction, a partial or complete E/Z isomerization of the enone moiety was observed in some cases prior to the cyclization, which resulted in a mixture of diastereomeric products. Use of a Cu(II)-bisoxazoline complex prevented the isomerization, allowing ...
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Experimental and Theoretical Studies on the Nazarov Cyclization/Wagner–Meerwein Rearrangement Sequence
2012Co-Authors: David Lebœuf, Vincent Gandon, Jennifer Ciesielski, Alison J. FrontierAbstract:Highly functionalized cyclopentenones can be generated by a chemoselective copper(II)-mediated Nazarov/Wagner–Meerwein Rearrangement sequence of divinyl ketones. A detailed investigation of this sequence is described including a study of substrate scope and limitations. After the initial 4π electrocyclization, this reaction proceeds via two different sequential [1,2]-shifts, with selectivity that depends upon either migratory ability or the steric bulkiness of the substituents at C1 and C5. This methodology allows the creation of vicinal stereogenic centers, including adjacent quaternary centers. This sequence can also be achieved by using a catalytic amount of copper(II) in combination with NaBAr4f, a weak Lewis acid. During the study of the scope of the reaction, a partial or complete E/Z isomerization of the enone moiety was observed in some cases prior to the cyclization, which resulted in a mixture of diastereomeric products. Use of a Cu(II)-bisoxazoline complex prevented the isomerization, allowing high diastereoselectivity to be obtained in all substrate types. In addition, the reaction sequence was studied by DFT computations at the UB3LYP/6-31G(d,p) level, which are consistent with the proposed sequences observed, including E/Z isomerizations and chemoselective Wagner–Meerwein shifts
Jie Huang - One of the best experts on this subject based on the ideXlab platform.
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Using Nazarov Electrocyclization of Stage Chemoselective [1,2]-Migrations: Stereoselective Synthesis of Functionalized Cyclopentenones.
ChemInform, 2012Co-Authors: David Leboeuf, Jie Huang, Vincent Gandon, Alison J. FrontierAbstract:The title process is based on a stereospecific Cu(II)-mediated Nazarov cyclization/Wagner—Meerwein Rearrangement.
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Development of a Nazarov cyclization/Wagner-Meerwein Rearrangement sequence for the stereoselective synthesis of spirocycles.
Journal of the American Chemical Society, 2007Co-Authors: Jie Huang, Alison J. FrontierAbstract:A stereoselective Nazarov cyclization/Wagner−Meerwein Rearrangement sequence for the synthesis of spirocyclic compounds was developed. While a range of different substrate types engaged in the cyclization/Rearrangement sequence, it was found that different substrates underwent different reaction pathways. Depending on the substitution pattern of the substrate, the sequence was terminated by either a hydride shift or the shift of a vinyl or aryl group. It was also possible to install adjacent quaternary stereocenters using this protocol. The efficiency of the Wagner−Meerwein Rearrangement was found to be dependent upon both the type and the amount of promoter used to generate the intermediate oxyallyl cation.
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development of a nazarov cyclization Wagner Meerwein Rearrangement sequence for the stereoselective synthesis of spirocycles
Journal of the American Chemical Society, 2007Co-Authors: Jie Huang, Alison J. FrontierAbstract:A stereoselective Nazarov cyclization/Wagner−Meerwein Rearrangement sequence for the synthesis of spirocyclic compounds was developed. While a range of different substrate types engaged in the cyclization/Rearrangement sequence, it was found that different substrates underwent different reaction pathways. Depending on the substitution pattern of the substrate, the sequence was terminated by either a hydride shift or the shift of a vinyl or aryl group. It was also possible to install adjacent quaternary stereocenters using this protocol. The efficiency of the Wagner−Meerwein Rearrangement was found to be dependent upon both the type and the amount of promoter used to generate the intermediate oxyallyl cation.
Satoshi Yokoshima - One of the best experts on this subject based on the ideXlab platform.
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synthesis of cardiopetaline via a Wagner Meerwein Rearrangement without preactivation of the pivotal hydroxy group
Organic Letters, 2017Co-Authors: Yoshitake Nishiyama, Satoshi Yokoshima, Tohru FukuyamaAbstract:A synthesis of cardiopetaline has been accomplished via a Wagner–Meerwein Rearrangement of a diol having the denudatine skeleton. The Wagner–Meerwein Rearrangement could be facilitated simply by heating the diol with p-toluenesulfonic acid in pivalic acid, without preactivating the pivotal hydroxy group. This strategy does not require differentiation of several hydroxy groups in the substrate for the Wagner–Meerwein Rearrangement and could be applied to the synthesis of more highly oxygenated aconitine-type diterpenoid alkaloids.
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Synthesis of Cardiopetaline via a Wagner–Meerwein Rearrangement without Preactivation of the Pivotal Hydroxy Group
Organic letters, 2017Co-Authors: Yoshitake Nishiyama, Satoshi Yokoshima, Tohru FukuyamaAbstract:A synthesis of cardiopetaline has been accomplished via a Wagner–Meerwein Rearrangement of a diol having the denudatine skeleton. The Wagner–Meerwein Rearrangement could be facilitated simply by heating the diol with p-toluenesulfonic acid in pivalic acid, without preactivating the pivotal hydroxy group. This strategy does not require differentiation of several hydroxy groups in the substrate for the Wagner–Meerwein Rearrangement and could be applied to the synthesis of more highly oxygenated aconitine-type diterpenoid alkaloids.
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Synthesis of Cardiopetaline via a Wagner–Meerwein Rearrangement without Preactivation of the Pivotal Hydroxy Group
2017Co-Authors: Yoshitake Nishiyama, Satoshi Yokoshima, Tohru FukuyamaAbstract:A synthesis of cardiopetaline has been accomplished via a Wagner–Meerwein Rearrangement of a diol having the denudatine skeleton. The Wagner–Meerwein Rearrangement could be facilitated simply by heating the diol with p-toluenesulfonic acid in pivalic acid, without preactivating the pivotal hydroxy group. This strategy does not require differentiation of several hydroxy groups in the substrate for the Wagner–Meerwein Rearrangement and could be applied to the synthesis of more highly oxygenated aconitine-type diterpenoid alkaloids
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Total Synthesis of (−)-Cardiopetaline
Organic letters, 2016Co-Authors: Yoshitake Nishiyama, Satoshi Yokoshima, Tohru FukuyamaAbstract:The total synthesis of (−)-cardiopetaline, an aconitine-type natural product, has been accomplished. Our synthesis involved a Wagner–Meerwein Rearrangement of a sulfonyloxirane that enabled, in a single step, the construction of the bicyclo[3.2.1] system in the aconitine skeleton and effective introduction of oxygen functional groups at the appropriate positions.
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Total synthesis of (-)-isoschizogamine.
Journal of the American Chemical Society, 2012Co-Authors: Yusuke Miura, Satoshi Yokoshima, Noriyuki Hayashi, Tohru FukuyamaAbstract:A first asymmetric total synthesis of (−)-isoschizogamine has been accomplished. Our synthesis features the facile construction of the carbon framework of the natural product through a Wagner–Meerwein Rearrangement, a tandem metathesis, a stereoselective rhodium-mediated 1,4-addition of an arylboronic acid, and a ring-closing metathesis via a hemiaminal ether.