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Trond Vidar Hansen - One of the best experts on this subject based on the ideXlab platform.
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catalytic enantioselective Iodolactonization reactions
Organic and Biomolecular Chemistry, 2019Co-Authors: Renate Kristianslund, Jorn Eivind Tungen, Trond Vidar HansenAbstract:The halolactonization reaction is a useful chemical transformation for the construction of lactones from γ- or δ-substituted alkenoic carboxylic acids or carboxylic esters. Traditionally, the stereoselectivity of these reactions has been controlled by the substrates or the reagents. The substrate-controlled method has been extensively studied and applied in the synthesis of many natural products. However, catalytic, enantioselective Iodolactonizations of γ- or δ-substituted alkenoic carboxylic acids have only recently been developed. This review article highlights the advances that have emerged over the last decade.
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squaramide catalyzed enantioselective Iodolactonization of allenoic acids
Tetrahedron Letters, 2016Co-Authors: Renate Kristianslund, Jorn Eivind Tungen, Marius Aursnes, Trond Vidar HansenAbstract:An asymmetric Iodolactonization reaction of allenoic acids has been extensively studied. Eight different chiral squaramides were prepared in a straightforward manner and investigated as organocatalysts. The reaction protocol is operationally simple to execute and proceeds with up to 76% enantiomeric excess. Several conditions, additives, catalysts, and substrates have been investigated. The best results were observed with 3-((3,5-bis(trifluoromethyl)phenyl)amino)-4-(((1R,2R)-2-(dipentylamino)cyclohexyl)amino)-cyclobut-3-ene-1,2-dione as the catalyst.
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asymmetric Iodolactonization an evolutionary account
European Journal of Organic Chemistry, 2014Co-Authors: Jens M J Nolsoe, Trond Vidar HansenAbstract:The diversity entailed by halolactonization makes it a fundamental transformation, enabling the synthetic organic chemist to build up molecular complexity in a way that relates structural elements in a predictable manner. Due to practical aspects and the subsequent flexible manipulation of the installed halogen handle, Iodolactonization takes precedence over the other variants. The asymmetry that can be conferred on the products by iodine-induced cyclization has been the subject of various approaches. For a long time stereoselectivity has been achieved by substrate-controlled reactions. However, lately, the reagent-controlled counterpart has surfaced as an alternative based on the action of a catalyst. Despite the fact that the current progress in catalytic asymmetric Iodolactonization has happened only in the space of the last three years, a number of conceptually different approaches have already been applied to advance beyond the substrate-controlled reaction. Herein we describe the various strategies, which have propelled the development of asymmetric Iodolactonization to its current state, putting an emphasis on catalysis.
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an asymmetric Iodolactonization reaction catalyzed by a zinc bis proline phenol complex
Tetrahedron Letters, 2014Co-Authors: Liudmila Filippova, Trond Vidar Hansen, Yngve StenstromAbstract:The intramolecular zinc bis-proline-phenol complex 2a was found to promote enantioselective Iodolactonization reactions of both electron-rich and electron-poor 5-aryl-5-hexenoic acids affording δ-iodolactones in good chemical yields with up to 82% enantiomeric excess. The reactions were found to be insensitive to air and moisture, providing an experimentally simple protocol for synthetically useful compounds.
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An asymmetric Iodolactonization reaction catalyzed by a zinc bis-proline–phenol complex
Tetrahedron Letters, 2014Co-Authors: Liudmila Filippova, Yngve Stenstrom, Trond Vidar HansenAbstract:The intramolecular zinc bis-proline-phenol complex 2a was found to promote enantioselective Iodolactonization reactions of both electron-rich and electron-poor 5-aryl-5-hexenoic acids affording δ-iodolactones in good chemical yields with up to 82% enantiomeric excess. The reactions were found to be insensitive to air and moisture, providing an experimentally simple protocol for synthetically useful compounds.
Takayoshi Arai - One of the best experts on this subject based on the ideXlab platform.
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Association of Halogen Bonding and Hydrogen Bonding in Metal Acetate-Catalyzed Asymmetric Halolactonization.
iScience, 2019Co-Authors: Takayoshi Arai, Kodai Horigane, Ohji Watanabe, Junki Kakino, Noriyuki Sugiyama, Hiroki Makino, Yuto Kamei, Shinnosuke Yabe, Masahiro YamanakaAbstract:Summary Cooperative activation using halogen bonding and hydrogen bonding works in metal-catalyzed asymmetric halolactonization. The Zn3(OAc)4-3,3′-bis(aminoimino)binaphthoxide (tri-Zn) complex catalyzes both asymmetric Iodolactonization and bromolactonization. Carboxylic acid substrates are converted to zinc carboxylates on the tri-Zn complex, and the N-halosuccinimide (N-bromosuccinimide [NBS] or N-iodosuccinimide [NIS]) is activated by hydrogen bonding with the diamine unit of chiral ligand. Halolactonization is significantly enhanced by the addition of catalytic I2. Density functional theory calculations revealed that a catalytic amount of I2 mediates the alkene portion of the substrates and NIS to realize highly enantioselective Iodolactonization. The tri-Zn catalyst activates both sides of the carboxylic acid and alkene moiety, so that asymmetric five-membered Iodolactonization of prochiral diallyl acetic acids proceeded to afford the chiral γ-butyrolactones. In the total description of the catalytic cycle, Iodolactonization using the NIS-I2 complex proceeds with the regeneration of I2, which enables the catalytic use of I2. The actual iodination reagent is I2 and not NIS.
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recyclable poly zn3 oac 4 3 3 bis aminoimino binaphthoxide catalyst for asymmetric Iodolactonization
Chemcatchem, 2015Co-Authors: Takayoshi Arai, Ohji Watanabe, Takahiro Kojima, Tsutomu Itoh, Hirofumi KanohAbstract:On the basis of the structure of the unimolecular Zn3(OAc)4–3,3′-bis(aminoimino)binaphthoxide complex, a poly-Zn3(OAc)4–3,3′-bis(aminoimino)binaphthoxide (poly-Zn) complex was prepared from 3,3′-diformylbinaphthol, tetramine, and Zn(OAc)2. The first-generation poly-Zn catalyst (poly-Zn1) was prepared from poly(aminoiminobinaphthol) and Zn(OAc)2. Although poly-Zn1 showed high catalytic activity for Iodolactonization, the catalyst could not be reused. The second-generation poly-Zn catalyst (poly-Zn2) was prepared by the self-organization of 3,3′-diformylbinaphthol, tetramine, and Zn(OAc)2. This produced a stable and active poly-Zn2 catalyst for asymmetric Iodolactonization that was reused over five cycles.
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Recyclable Poly‐Zn3(OAc)4–3,3′‐Bis(aminoimino)binaphthoxide Catalyst for Asymmetric Iodolactonization
Chemcatchem, 2015Co-Authors: Takayoshi Arai, Ohji Watanabe, Takahiro Kojima, Tsutomu Itoh, Hirofumi KanohAbstract:On the basis of the structure of the unimolecular Zn3(OAc)4–3,3′-bis(aminoimino)binaphthoxide complex, a poly-Zn3(OAc)4–3,3′-bis(aminoimino)binaphthoxide (poly-Zn) complex was prepared from 3,3′-diformylbinaphthol, tetramine, and Zn(OAc)2. The first-generation poly-Zn catalyst (poly-Zn1) was prepared from poly(aminoiminobinaphthol) and Zn(OAc)2. Although poly-Zn1 showed high catalytic activity for Iodolactonization, the catalyst could not be reused. The second-generation poly-Zn catalyst (poly-Zn2) was prepared by the self-organization of 3,3′-diformylbinaphthol, tetramine, and Zn(OAc)2. This produced a stable and active poly-Zn2 catalyst for asymmetric Iodolactonization that was reused over five cycles.
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a trinuclear zn3 oac 4 3 3 bis aminoimino binaphthoxide complex for highly efficient catalytic asymmetric Iodolactonization
Chemical Communications, 2014Co-Authors: Takayoshi Arai, Noriyuki Sugiyama, Shinnosuke Yabe, Hyuma Masu, Sayaka Kado, Masahiro YamanakaAbstract:A 3,3′-bis(aminoimino)BINOL ligand was newly designed and synthesized for the formation of a trinuclear Zn complex upon reaction with Zn(OAc)2. Using the harmony of the tri-zinc atoms, 1 mol% Zn3(OAc)4-3,3′-bis(aminoimino)binaphthoxide catalyzed asymmetric Iodolactonization in up to 99.9% ee.
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A trinuclear Zn3(OAc)4-3,3′-bis(aminoimino)binaphthoxide complex for highly efficient catalytic asymmetric Iodolactonization
Chemical Communications, 2014Co-Authors: Takayoshi Arai, Noriyuki Sugiyama, Shinnosuke Yabe, Hyuma Masu, Sayaka Kado, Masahiro YamanakaAbstract:A 3,3′-bis(aminoimino)BINOL ligand was newly designed and synthesized for the formation of a trinuclear Zn complex upon reaction with Zn(OAc)2. Using the harmony of the tri-zinc atoms, 1 mol% Zn3(OAc)4-3,3′-bis(aminoimino)binaphthoxide catalyzed asymmetric Iodolactonization in up to 99.9% ee.
Hirofumi Kanoh - One of the best experts on this subject based on the ideXlab platform.
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recyclable poly zn3 oac 4 3 3 bis aminoimino binaphthoxide catalyst for asymmetric Iodolactonization
Chemcatchem, 2015Co-Authors: Takayoshi Arai, Ohji Watanabe, Takahiro Kojima, Tsutomu Itoh, Hirofumi KanohAbstract:On the basis of the structure of the unimolecular Zn3(OAc)4–3,3′-bis(aminoimino)binaphthoxide complex, a poly-Zn3(OAc)4–3,3′-bis(aminoimino)binaphthoxide (poly-Zn) complex was prepared from 3,3′-diformylbinaphthol, tetramine, and Zn(OAc)2. The first-generation poly-Zn catalyst (poly-Zn1) was prepared from poly(aminoiminobinaphthol) and Zn(OAc)2. Although poly-Zn1 showed high catalytic activity for Iodolactonization, the catalyst could not be reused. The second-generation poly-Zn catalyst (poly-Zn2) was prepared by the self-organization of 3,3′-diformylbinaphthol, tetramine, and Zn(OAc)2. This produced a stable and active poly-Zn2 catalyst for asymmetric Iodolactonization that was reused over five cycles.
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Recyclable Poly‐Zn3(OAc)4–3,3′‐Bis(aminoimino)binaphthoxide Catalyst for Asymmetric Iodolactonization
Chemcatchem, 2015Co-Authors: Takayoshi Arai, Ohji Watanabe, Takahiro Kojima, Tsutomu Itoh, Hirofumi KanohAbstract:On the basis of the structure of the unimolecular Zn3(OAc)4–3,3′-bis(aminoimino)binaphthoxide complex, a poly-Zn3(OAc)4–3,3′-bis(aminoimino)binaphthoxide (poly-Zn) complex was prepared from 3,3′-diformylbinaphthol, tetramine, and Zn(OAc)2. The first-generation poly-Zn catalyst (poly-Zn1) was prepared from poly(aminoiminobinaphthol) and Zn(OAc)2. Although poly-Zn1 showed high catalytic activity for Iodolactonization, the catalyst could not be reused. The second-generation poly-Zn catalyst (poly-Zn2) was prepared by the self-organization of 3,3′-diformylbinaphthol, tetramine, and Zn(OAc)2. This produced a stable and active poly-Zn2 catalyst for asymmetric Iodolactonization that was reused over five cycles.
Masahiro Yamanaka - One of the best experts on this subject based on the ideXlab platform.
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Association of Halogen Bonding and Hydrogen Bonding in Metal Acetate-Catalyzed Asymmetric Halolactonization.
iScience, 2019Co-Authors: Takayoshi Arai, Kodai Horigane, Ohji Watanabe, Junki Kakino, Noriyuki Sugiyama, Hiroki Makino, Yuto Kamei, Shinnosuke Yabe, Masahiro YamanakaAbstract:Summary Cooperative activation using halogen bonding and hydrogen bonding works in metal-catalyzed asymmetric halolactonization. The Zn3(OAc)4-3,3′-bis(aminoimino)binaphthoxide (tri-Zn) complex catalyzes both asymmetric Iodolactonization and bromolactonization. Carboxylic acid substrates are converted to zinc carboxylates on the tri-Zn complex, and the N-halosuccinimide (N-bromosuccinimide [NBS] or N-iodosuccinimide [NIS]) is activated by hydrogen bonding with the diamine unit of chiral ligand. Halolactonization is significantly enhanced by the addition of catalytic I2. Density functional theory calculations revealed that a catalytic amount of I2 mediates the alkene portion of the substrates and NIS to realize highly enantioselective Iodolactonization. The tri-Zn catalyst activates both sides of the carboxylic acid and alkene moiety, so that asymmetric five-membered Iodolactonization of prochiral diallyl acetic acids proceeded to afford the chiral γ-butyrolactones. In the total description of the catalytic cycle, Iodolactonization using the NIS-I2 complex proceeds with the regeneration of I2, which enables the catalytic use of I2. The actual iodination reagent is I2 and not NIS.
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a trinuclear zn3 oac 4 3 3 bis aminoimino binaphthoxide complex for highly efficient catalytic asymmetric Iodolactonization
Chemical Communications, 2014Co-Authors: Takayoshi Arai, Noriyuki Sugiyama, Shinnosuke Yabe, Hyuma Masu, Sayaka Kado, Masahiro YamanakaAbstract:A 3,3′-bis(aminoimino)BINOL ligand was newly designed and synthesized for the formation of a trinuclear Zn complex upon reaction with Zn(OAc)2. Using the harmony of the tri-zinc atoms, 1 mol% Zn3(OAc)4-3,3′-bis(aminoimino)binaphthoxide catalyzed asymmetric Iodolactonization in up to 99.9% ee.
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A trinuclear Zn3(OAc)4-3,3′-bis(aminoimino)binaphthoxide complex for highly efficient catalytic asymmetric Iodolactonization
Chemical Communications, 2014Co-Authors: Takayoshi Arai, Noriyuki Sugiyama, Shinnosuke Yabe, Hyuma Masu, Sayaka Kado, Masahiro YamanakaAbstract:A 3,3′-bis(aminoimino)BINOL ligand was newly designed and synthesized for the formation of a trinuclear Zn complex upon reaction with Zn(OAc)2. Using the harmony of the tri-zinc atoms, 1 mol% Zn3(OAc)4-3,3′-bis(aminoimino)binaphthoxide catalyzed asymmetric Iodolactonization in up to 99.9% ee.
Mark J Kurth - One of the best experts on this subject based on the ideXlab platform.
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comparison of solid phase and solution phase chiral auxiliaries in the alkylation Iodolactonization sequence to γ butyrolactones
Journal of Organic Chemistry, 2002Co-Authors: Michael D Price, Mark J Kurth, Neil E SchoreAbstract:Five prolinol-based chiral auxilaries have been compared for the stereoselective synthesis of γ-butyrolactones via the sequence of N-acylation, Cα-allylation, and Iodolactonization under both solution-phase and solid-phase conditions. Comparisons of stereoselectivity of both the Cα-allylation and Iodolactonization processes indicate that incorporation of a non-C2-symmetric auxiliary as a polymer cross-link gives results superior to those obtained either in solution or with other non-C2-symmetric auxiliaries and comparable to those observed using a polymer-supported pseudo-C2-symmetric auxiliary.
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Comparison of Solid-Phase and Solution-Phase Chiral Auxiliaries in the Alkylation/Iodolactonization Sequence to γ-Butyrolactones
Journal of Organic Chemistry, 2002Co-Authors: Michael D Price, Mark J Kurth, Neil E SchoreAbstract:Five prolinol-based chiral auxilaries have been compared for the stereoselective synthesis of γ-butyrolactones via the sequence of N-acylation, Cα-allylation, and Iodolactonization under both solution-phase and solid-phase conditions. Comparisons of stereoselectivity of both the Cα-allylation and Iodolactonization processes indicate that incorporation of a non-C2-symmetric auxiliary as a polymer cross-link gives results superior to those obtained either in solution or with other non-C2-symmetric auxiliaries and comparable to those observed using a polymer-supported pseudo-C2-symmetric auxiliary.
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Regioselectivity in the Iodolactonization of 1,6-heptadien-4-carboxylic acid derivatives
Tetrahedron Letters, 2001Co-Authors: Mark J Kurth, Edward G. Brown, Eric J. Lewis, John C. MckewAbstract:Abstract Electronic control, as a consequence of differential olefin substitution, and a comparison of conformational versus electronic control in the Iodolactonization of 1,6-heptadien-4-carboxylic acid derivatives are reported.
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A polymer-supported C2-symmetric chiral auxiliary: Preparation of non-racemic 3,5-disubstituted-γ-butyrolactones
Tetrahedron Letters, 1994Co-Authors: Hong Sik Moon, Neil E Schore, Mark J KurthAbstract:A polymer-bound “C2-symmetric” pyrrolidine-based auxiliary is reported and shown to serve an effective control element for a three-step process consisting of N-acylation, Cα-alkylation, and subsequent Iodolactonization to deliver optically active 3,5-disubstituted-γ-butyrolactone.
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Doubly Diastereoselective Iodolactonizations: Olefin and Face Selectivity in Nona-2,7-diene-5-carboxylic Acid Cyclizations
Journal of Organic Chemistry, 1994Co-Authors: John C. Mckew, Marilyn M. Olmstead, Mark J KurthAbstract:Nonracemic nonadienoic acids (v) were subjected to Iodolactonization conditions and, by doubly diastereoselective cyclization, delivered enantiomerically pure iodo lactones replete with up to five contiguous stereogenic centers
