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Hua Yang - One of the best experts on this subject based on the ideXlab platform.
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enantiospecific total synthesis of tanikolide via a key 2 3 Meisenheimer Rearrangement with an allylic amine n oxide directed epoxidation and a one pot trichloroisocyanuric acid n debenzylation and n chlorination
Journal of Organic Chemistry, 2013Co-Authors: Yangla Xie, Moran Sun, Hang Zhou, Qiwei Cao, Kaige Gao, Changling Niu, Hua YangAbstract:The enantiospecific total synthesis of the δ-lactonic marine natural product (+)-tanikolide (1), isolated from Lyngbya majuscula , was achieved using a [2,3]-Meisenheimer Rearrangement as the key reaction. During this Rearrangement, we discovered that the allylic amine N-oxide could direct the m-CPBA double-bond epoxidation to the syn position. The resulting syn product 8 underwent epoxide ring opening under the m-CBA conditions to give the five- and six-membered cyclic ether amine N-oxides, which we further treated with Zn and conc. HCl to obtain the reduced bisbenzyl tertiary amines 23 and 22, respectively. When 23 and 22 were treated with trichloroisocyanuric acid (TCCA) in dichloromethane, oxidation at the benzyl position occurred, forming iminium ions. These intermediates were trapped by intramolecular reaction with the hydroxyls, and the resulting intermediates were then oxidized or shifted to afford 25 and 24, respectively. The entire one-pot process involves N-debenzylation, N-chlorination, and hemiacetal oxidation. The amine N-oxide-directed epoxidation complements Davies' ammonium-directed epoxidation. Thus, TCCA N-debenzylation is described for the first time and might be a useful N-debenzylation technique.
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Construction of Chiral Tertiary Alcohol Stereocenters via the [2,3]- Meisenheimer Rearrangement: Enantioselective Synthesis of the Side-Chain Acids of Homoharringtonine and Harringtonine
2013Co-Authors: Hua Yang, Yangla Xie, Moran Sun, Shuguang Zhao, Ming Zhu, Changling NiuAbstract:For the first time, the [2,3]-Meisenheimer Rearrangement has been developed into a general strategy for the construction of chiral tertiary alcohols. The effectiveness and practicality of this methodology are illustrated by the successful synthesis of (R)-20 and (R)-30, the side chain acids of homoharringtonine and harringtonine, respectively
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Enantiospecific Total Synthesis of (+)-Tanikolide via a Key [2,3]-Meisenheimer Rearrangement with an Allylic Amine N‑Oxide-Directed Epoxidation and a One-Pot Trichloroisocyanuric Acid N‑Debenzylation and N‑Chlorination
2013Co-Authors: Yangla Xie, Moran Sun, Hang Zhou, Qiwei Cao, Kaige Gao, Changling Niu, Hua YangAbstract:The enantiospecific total synthesis of the δ-lactonic marine natural product (+)-tanikolide (1), isolated from Lyngbya majuscula, was achieved using a [2,3]-Meisenheimer Rearrangement as the key reaction. During this Rearrangement, we discovered that the allylic amine N-oxide could direct the m-CPBA double-bond epoxidation to the syn position. The resulting syn product 8 underwent epoxide ring opening under the m-CBA conditions to give the five- and six-membered cyclic ether amine N-oxides, which we further treated with Zn and conc. HCl to obtain the reduced bisbenzyl tertiary amines 23 and 22, respectively. When 23 and 22 were treated with trichloroisocyanuric acid (TCCA) in dichloromethane, oxidation at the benzyl position occurred, forming iminium ions. These intermediates were trapped by intramolecular reaction with the hydroxyls, and the resulting intermediates were then oxidized or shifted to afford 25 and 24, respectively. The entire one-pot process involves N-debenzylation, N-chlorination, and hemiacetal oxidation. The amine N-oxide-directed epoxidation complements Davies’ ammonium-directed epoxidation. Thus, TCCA N-debenzylation is described for the first time and might be a useful N-debenzylation technique
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Construction of chiral tertiary alcohol stereocenters via the [2,3]-Meisenheimer Rearrangement: enantioselective synthesis of the side-chain acids of homoharringtonine and harringtonine.
The Journal of organic chemistry, 2012Co-Authors: Hua Yang, Yangla Xie, Moran Sun, Shuguang Zhao, Ming Zhu, Changling NiuAbstract:For the first time, the [2,3]-Meisenheimer Rearrangement has been developed into a general strategy for the construction of chiral tertiary alcohols. The effectiveness and practicality of this methodology are illustrated by the successful synthesis of (R)-20 and (R)-30, the side chain acids of homoharringtonine and harringtonine, respectively.
Changling Niu - One of the best experts on this subject based on the ideXlab platform.
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enantiospecific total synthesis of tanikolide via a key 2 3 Meisenheimer Rearrangement with an allylic amine n oxide directed epoxidation and a one pot trichloroisocyanuric acid n debenzylation and n chlorination
Journal of Organic Chemistry, 2013Co-Authors: Yangla Xie, Moran Sun, Hang Zhou, Qiwei Cao, Kaige Gao, Changling Niu, Hua YangAbstract:The enantiospecific total synthesis of the δ-lactonic marine natural product (+)-tanikolide (1), isolated from Lyngbya majuscula , was achieved using a [2,3]-Meisenheimer Rearrangement as the key reaction. During this Rearrangement, we discovered that the allylic amine N-oxide could direct the m-CPBA double-bond epoxidation to the syn position. The resulting syn product 8 underwent epoxide ring opening under the m-CBA conditions to give the five- and six-membered cyclic ether amine N-oxides, which we further treated with Zn and conc. HCl to obtain the reduced bisbenzyl tertiary amines 23 and 22, respectively. When 23 and 22 were treated with trichloroisocyanuric acid (TCCA) in dichloromethane, oxidation at the benzyl position occurred, forming iminium ions. These intermediates were trapped by intramolecular reaction with the hydroxyls, and the resulting intermediates were then oxidized or shifted to afford 25 and 24, respectively. The entire one-pot process involves N-debenzylation, N-chlorination, and hemiacetal oxidation. The amine N-oxide-directed epoxidation complements Davies' ammonium-directed epoxidation. Thus, TCCA N-debenzylation is described for the first time and might be a useful N-debenzylation technique.
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Construction of Chiral Tertiary Alcohol Stereocenters via the [2,3]- Meisenheimer Rearrangement: Enantioselective Synthesis of the Side-Chain Acids of Homoharringtonine and Harringtonine
2013Co-Authors: Hua Yang, Yangla Xie, Moran Sun, Shuguang Zhao, Ming Zhu, Changling NiuAbstract:For the first time, the [2,3]-Meisenheimer Rearrangement has been developed into a general strategy for the construction of chiral tertiary alcohols. The effectiveness and practicality of this methodology are illustrated by the successful synthesis of (R)-20 and (R)-30, the side chain acids of homoharringtonine and harringtonine, respectively
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Enantiospecific Total Synthesis of (+)-Tanikolide via a Key [2,3]-Meisenheimer Rearrangement with an Allylic Amine N‑Oxide-Directed Epoxidation and a One-Pot Trichloroisocyanuric Acid N‑Debenzylation and N‑Chlorination
2013Co-Authors: Yangla Xie, Moran Sun, Hang Zhou, Qiwei Cao, Kaige Gao, Changling Niu, Hua YangAbstract:The enantiospecific total synthesis of the δ-lactonic marine natural product (+)-tanikolide (1), isolated from Lyngbya majuscula, was achieved using a [2,3]-Meisenheimer Rearrangement as the key reaction. During this Rearrangement, we discovered that the allylic amine N-oxide could direct the m-CPBA double-bond epoxidation to the syn position. The resulting syn product 8 underwent epoxide ring opening under the m-CBA conditions to give the five- and six-membered cyclic ether amine N-oxides, which we further treated with Zn and conc. HCl to obtain the reduced bisbenzyl tertiary amines 23 and 22, respectively. When 23 and 22 were treated with trichloroisocyanuric acid (TCCA) in dichloromethane, oxidation at the benzyl position occurred, forming iminium ions. These intermediates were trapped by intramolecular reaction with the hydroxyls, and the resulting intermediates were then oxidized or shifted to afford 25 and 24, respectively. The entire one-pot process involves N-debenzylation, N-chlorination, and hemiacetal oxidation. The amine N-oxide-directed epoxidation complements Davies’ ammonium-directed epoxidation. Thus, TCCA N-debenzylation is described for the first time and might be a useful N-debenzylation technique
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Construction of chiral tertiary alcohol stereocenters via the [2,3]-Meisenheimer Rearrangement: enantioselective synthesis of the side-chain acids of homoharringtonine and harringtonine.
The Journal of organic chemistry, 2012Co-Authors: Hua Yang, Yangla Xie, Moran Sun, Shuguang Zhao, Ming Zhu, Changling NiuAbstract:For the first time, the [2,3]-Meisenheimer Rearrangement has been developed into a general strategy for the construction of chiral tertiary alcohols. The effectiveness and practicality of this methodology are illustrated by the successful synthesis of (R)-20 and (R)-30, the side chain acids of homoharringtonine and harringtonine, respectively.
Yangla Xie - One of the best experts on this subject based on the ideXlab platform.
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enantiospecific total synthesis of tanikolide via a key 2 3 Meisenheimer Rearrangement with an allylic amine n oxide directed epoxidation and a one pot trichloroisocyanuric acid n debenzylation and n chlorination
Journal of Organic Chemistry, 2013Co-Authors: Yangla Xie, Moran Sun, Hang Zhou, Qiwei Cao, Kaige Gao, Changling Niu, Hua YangAbstract:The enantiospecific total synthesis of the δ-lactonic marine natural product (+)-tanikolide (1), isolated from Lyngbya majuscula , was achieved using a [2,3]-Meisenheimer Rearrangement as the key reaction. During this Rearrangement, we discovered that the allylic amine N-oxide could direct the m-CPBA double-bond epoxidation to the syn position. The resulting syn product 8 underwent epoxide ring opening under the m-CBA conditions to give the five- and six-membered cyclic ether amine N-oxides, which we further treated with Zn and conc. HCl to obtain the reduced bisbenzyl tertiary amines 23 and 22, respectively. When 23 and 22 were treated with trichloroisocyanuric acid (TCCA) in dichloromethane, oxidation at the benzyl position occurred, forming iminium ions. These intermediates were trapped by intramolecular reaction with the hydroxyls, and the resulting intermediates were then oxidized or shifted to afford 25 and 24, respectively. The entire one-pot process involves N-debenzylation, N-chlorination, and hemiacetal oxidation. The amine N-oxide-directed epoxidation complements Davies' ammonium-directed epoxidation. Thus, TCCA N-debenzylation is described for the first time and might be a useful N-debenzylation technique.
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Construction of Chiral Tertiary Alcohol Stereocenters via the [2,3]- Meisenheimer Rearrangement: Enantioselective Synthesis of the Side-Chain Acids of Homoharringtonine and Harringtonine
2013Co-Authors: Hua Yang, Yangla Xie, Moran Sun, Shuguang Zhao, Ming Zhu, Changling NiuAbstract:For the first time, the [2,3]-Meisenheimer Rearrangement has been developed into a general strategy for the construction of chiral tertiary alcohols. The effectiveness and practicality of this methodology are illustrated by the successful synthesis of (R)-20 and (R)-30, the side chain acids of homoharringtonine and harringtonine, respectively
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Enantiospecific Total Synthesis of (+)-Tanikolide via a Key [2,3]-Meisenheimer Rearrangement with an Allylic Amine N‑Oxide-Directed Epoxidation and a One-Pot Trichloroisocyanuric Acid N‑Debenzylation and N‑Chlorination
2013Co-Authors: Yangla Xie, Moran Sun, Hang Zhou, Qiwei Cao, Kaige Gao, Changling Niu, Hua YangAbstract:The enantiospecific total synthesis of the δ-lactonic marine natural product (+)-tanikolide (1), isolated from Lyngbya majuscula, was achieved using a [2,3]-Meisenheimer Rearrangement as the key reaction. During this Rearrangement, we discovered that the allylic amine N-oxide could direct the m-CPBA double-bond epoxidation to the syn position. The resulting syn product 8 underwent epoxide ring opening under the m-CBA conditions to give the five- and six-membered cyclic ether amine N-oxides, which we further treated with Zn and conc. HCl to obtain the reduced bisbenzyl tertiary amines 23 and 22, respectively. When 23 and 22 were treated with trichloroisocyanuric acid (TCCA) in dichloromethane, oxidation at the benzyl position occurred, forming iminium ions. These intermediates were trapped by intramolecular reaction with the hydroxyls, and the resulting intermediates were then oxidized or shifted to afford 25 and 24, respectively. The entire one-pot process involves N-debenzylation, N-chlorination, and hemiacetal oxidation. The amine N-oxide-directed epoxidation complements Davies’ ammonium-directed epoxidation. Thus, TCCA N-debenzylation is described for the first time and might be a useful N-debenzylation technique
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Construction of chiral tertiary alcohol stereocenters via the [2,3]-Meisenheimer Rearrangement: enantioselective synthesis of the side-chain acids of homoharringtonine and harringtonine.
The Journal of organic chemistry, 2012Co-Authors: Hua Yang, Yangla Xie, Moran Sun, Shuguang Zhao, Ming Zhu, Changling NiuAbstract:For the first time, the [2,3]-Meisenheimer Rearrangement has been developed into a general strategy for the construction of chiral tertiary alcohols. The effectiveness and practicality of this methodology are illustrated by the successful synthesis of (R)-20 and (R)-30, the side chain acids of homoharringtonine and harringtonine, respectively.
Moran Sun - One of the best experts on this subject based on the ideXlab platform.
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enantiospecific total synthesis of tanikolide via a key 2 3 Meisenheimer Rearrangement with an allylic amine n oxide directed epoxidation and a one pot trichloroisocyanuric acid n debenzylation and n chlorination
Journal of Organic Chemistry, 2013Co-Authors: Yangla Xie, Moran Sun, Hang Zhou, Qiwei Cao, Kaige Gao, Changling Niu, Hua YangAbstract:The enantiospecific total synthesis of the δ-lactonic marine natural product (+)-tanikolide (1), isolated from Lyngbya majuscula , was achieved using a [2,3]-Meisenheimer Rearrangement as the key reaction. During this Rearrangement, we discovered that the allylic amine N-oxide could direct the m-CPBA double-bond epoxidation to the syn position. The resulting syn product 8 underwent epoxide ring opening under the m-CBA conditions to give the five- and six-membered cyclic ether amine N-oxides, which we further treated with Zn and conc. HCl to obtain the reduced bisbenzyl tertiary amines 23 and 22, respectively. When 23 and 22 were treated with trichloroisocyanuric acid (TCCA) in dichloromethane, oxidation at the benzyl position occurred, forming iminium ions. These intermediates were trapped by intramolecular reaction with the hydroxyls, and the resulting intermediates were then oxidized or shifted to afford 25 and 24, respectively. The entire one-pot process involves N-debenzylation, N-chlorination, and hemiacetal oxidation. The amine N-oxide-directed epoxidation complements Davies' ammonium-directed epoxidation. Thus, TCCA N-debenzylation is described for the first time and might be a useful N-debenzylation technique.
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Construction of Chiral Tertiary Alcohol Stereocenters via the [2,3]- Meisenheimer Rearrangement: Enantioselective Synthesis of the Side-Chain Acids of Homoharringtonine and Harringtonine
2013Co-Authors: Hua Yang, Yangla Xie, Moran Sun, Shuguang Zhao, Ming Zhu, Changling NiuAbstract:For the first time, the [2,3]-Meisenheimer Rearrangement has been developed into a general strategy for the construction of chiral tertiary alcohols. The effectiveness and practicality of this methodology are illustrated by the successful synthesis of (R)-20 and (R)-30, the side chain acids of homoharringtonine and harringtonine, respectively
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Enantiospecific Total Synthesis of (+)-Tanikolide via a Key [2,3]-Meisenheimer Rearrangement with an Allylic Amine N‑Oxide-Directed Epoxidation and a One-Pot Trichloroisocyanuric Acid N‑Debenzylation and N‑Chlorination
2013Co-Authors: Yangla Xie, Moran Sun, Hang Zhou, Qiwei Cao, Kaige Gao, Changling Niu, Hua YangAbstract:The enantiospecific total synthesis of the δ-lactonic marine natural product (+)-tanikolide (1), isolated from Lyngbya majuscula, was achieved using a [2,3]-Meisenheimer Rearrangement as the key reaction. During this Rearrangement, we discovered that the allylic amine N-oxide could direct the m-CPBA double-bond epoxidation to the syn position. The resulting syn product 8 underwent epoxide ring opening under the m-CBA conditions to give the five- and six-membered cyclic ether amine N-oxides, which we further treated with Zn and conc. HCl to obtain the reduced bisbenzyl tertiary amines 23 and 22, respectively. When 23 and 22 were treated with trichloroisocyanuric acid (TCCA) in dichloromethane, oxidation at the benzyl position occurred, forming iminium ions. These intermediates were trapped by intramolecular reaction with the hydroxyls, and the resulting intermediates were then oxidized or shifted to afford 25 and 24, respectively. The entire one-pot process involves N-debenzylation, N-chlorination, and hemiacetal oxidation. The amine N-oxide-directed epoxidation complements Davies’ ammonium-directed epoxidation. Thus, TCCA N-debenzylation is described for the first time and might be a useful N-debenzylation technique
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Construction of chiral tertiary alcohol stereocenters via the [2,3]-Meisenheimer Rearrangement: enantioselective synthesis of the side-chain acids of homoharringtonine and harringtonine.
The Journal of organic chemistry, 2012Co-Authors: Hua Yang, Yangla Xie, Moran Sun, Shuguang Zhao, Ming Zhu, Changling NiuAbstract:For the first time, the [2,3]-Meisenheimer Rearrangement has been developed into a general strategy for the construction of chiral tertiary alcohols. The effectiveness and practicality of this methodology are illustrated by the successful synthesis of (R)-20 and (R)-30, the side chain acids of homoharringtonine and harringtonine, respectively.
Gd Smyth - One of the best experts on this subject based on the ideXlab platform.
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Asymmetric synthesis of (R)-hexane-1,5-diol, (R)-hex-3-ene-1,5-diol and (R)-6-methylhept-5-en-2-ol (sulcatol) employing a tandem asymmetric conjugate addition and stereospecific Meisenheimer Rearrangement protocol
1996Co-Authors: Sg Davies, Gd SmythAbstract:Highly stereoselective conjugate addition of lithium (R)-N-methyl-(α-methylbenzyl)amide to tert-butyl (E,E)-hexa-2,4-dienoate, followed by reduction of the ester to the corresponding alcohol, affords a substrate which undergoes, upon oxidation, a stereospecific Meisenheimer Rearrangement to give a single diastereomer of the corresponding trialkylhydroxylamine. The analogous N-benzyl adduct gives lower yields in the oxidation-Rearrangement reaction. If the ester is not reduced to the alcohol, N-oxidation leads to Cope elimination, not Meisenheimer Rearrangement. Cleavage of the N-O bond gives (R)-hex-3-ene-1,5-diol, and hydrogenation of the double bond affords (R)-hexane-1,5-diol in high ee. This methodology has been applied to the synthesis of the insect pheromone (R)-6-methylhept-5-en-2-ol (sulcatol) from tert-butyl (E,E)-hexa-2,4-dienoate, via a sequence involving conjugate addition of the lithium amide, Grignard addition to the ester, Meisenheimer Rearrangement, hydrogenation of the double bond, dehydration of the tertiary alcohol and finally N-O bond cleavage
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Asymmetric synthesis of (R)-hexane-1,5-diol and (R)-hex-3-ene-1,5-diol via a tandem asymmetric conjugate addition stereospecific Meisenheimer Rearrangement protocol
1996Co-Authors: Sg Davies, Gd SmythAbstract:Stereoselective conjugate addition of (R)-lithium N,α-dimethylbenzylamide to tert-butyl (E,E)-hexa-2,4-dienoate, followed by reduction of the ester to the corresponding alcohol, affords a substrate which undergoes, on oxidation, a stereospecific Meisenheimer Rearrangement to give a single diastereomer of the corresponding trialkylhydroxylamine. Cleavage of the N-O bond gives (R)-hex-3-ene-1,5-diol and subsequent hydrogenation of the double bond affords (R)-hexane-1,5-diol in high e.e
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Asymmetric synthesis of (R)-sulcatol
1996Co-Authors: Sg Davies, Gd SmythAbstract:The insect pheromone (R)-sulcatol, 2-hydroxy-6-methylhept-5-ene, is synthesized via a stereoselective conjugate addition of (R)-lithium N,α-dimethylbenzylamide to tert-butyl (E,E)-hexa-2,4-dienoate, Grignard addition, and stereospecific Meisenheimer Rearrangement. Hydrogenation of the olefin, dehydration of the tertiary alcohol and N-O bond cleavage complete the synthesis