The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
David R. Mootoo - One of the best experts on this subject based on the ideXlab platform.
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Olefin metathesis-Iodoetherification-dehydroiodination strategy for spiroketal subunits of polyether antibiotics.
The Journal of Organic Chemistry, 2009Co-Authors: Kurissery A. Tony, Darrin Dabideen, Maria Dolores Díaz-hernández, Jesús Jiménez-barbero, David R. MootooAbstract:The convergent synthesis of two pentacyclic analogues of the polyether monensin A is described. Although different with respect to the configuration of the alcohol at the 3 position of the six-membered ring of the spiroketal subunit, the configuration at the acetal center in both structures is unchanged and is consistent with the anomeric effect. The key synthetic steps are the coupling of two complex segments via an olefin metathesis, and the subsequent conversion of a dihydroxyalkene to the spiroketal through an Iodoetherification−dehydroiodination sequence. The compatibility of these transformations with a variety of functional groups makes the overall strategy appropriate for highly substituted frameworks.
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an Iodoetherification dehydroiodination strategy for the synthesis of complex spiroketals from dihydroxyalkene precursors
Organic and Biomolecular Chemistry, 2008Co-Authors: Kurissery A. Tony, Darrin Dabideen, David R. MootooAbstract:Dihydroxyalkenes or their monoprotected alcohol derivatives are transformed to 5,5- and 5,6-spiroketals through a sequence involving an initial iodocyclization, followed by a silver triflate mediated spiroketalization step on the derived hydroxy-iodoether.
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An Iodoetherification–dehydroiodination strategy for the synthesis of complex spiroketals from dihydroxyalkene precursors
Organic & Biomolecular Chemistry, 2008Co-Authors: Kurissery A. Tony, Darrin Dabideen, David R. MootooAbstract:Dihydroxyalkenes or their monoprotected alcohol derivatives are transformed to 5,5- and 5,6-spiroketals through a sequence involving an initial iodocyclization, followed by a silver triflate mediated spiroketalization step on the derived hydroxy-iodoether.
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Synthesis of the ABCD trioxadispiroketal subunit of azaspiracid-1: an Iodoetherification-dehydroiodination strategy for complex spiroketals.
Organic Letters, 2007Co-Authors: David R. MootooAbstract:An unusual spiroketalization strategy in which a hydroxyalkene serves as a precursor to a cyclic enol ether was applied to the synthesis of the ABCD trioxadispiroketal subunit of azaspiracid-1. The trioxadispiroketal product, which represents a double anomeric effect, was obtained as a single trioxadispiroketal diastereomer. A key ploy in the synthesis of the CD segment was the use of a cyclopropane as a synthon for the C-14 methyl group.
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Highly functionalized trans-2,5-disubstituted tetrahydrofurans from ribofuranoside templates: precursors to linked polycyclic ethers☆
Tetrahedron Letters, 2003Co-Authors: Darrin Dabideen, David R. MootooAbstract:Iodoetherification of C5 allylated ribo-furanosides leads to trans-2,5-disubstituted tetrahydrofurans with high selectivity. The application of this reaction to the synthesis of complex polycyclic ethers is illustrated in the preparation of a truncated, tricyclic analog of monensin A.
Rodney A Fernandes - One of the best experts on this subject based on the ideXlab platform.
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pd catalyzed site selective mono allylic substitution and bis arylation by directed allylic c h activation synthesis of anti γ aryl styryl β hydroxy acids and highly substituted tetrahydrofurans
Journal of the American Chemical Society, 2016Co-Authors: Jothi L Nallasivam, Rodney A FernandesAbstract:An efficient palladium-catalyzed site-selective arylation of γ-vinyl-γ-lactone by aryl boronic acid has been developed. γ-Vinyl-γ-lactone 1a has been contemplated as allyl electrophile donor for allylic arylation via π-allyl palladium intermediate using 1.5 equiv of aryl boronic acid 2. Using 3.0 equiv of the latter resulted in mono-arylation by allylic substitution and subsequent site-selective second arylation by directed allylic C–H activation giving stereoselectively anti-γ-(aryl,styryl)-β-hydroxy acids. Presence of O2 was crucial for the second arylation via Pd(II) catalysis. Thus, a good synergy of dual catalysis by Pd(0) and Pd(II) was observed. This methodology has been elaborated to synthesize highly substituted tetrahydrofurans including aryl-Hagen’s gland lactone analogues via intramolecular Iodoetherification.
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Pd-Catalyzed Site-Selective Mono-allylic Substitution and Bis-arylation by Directed Allylic C–H Activation: Synthesis of anti-γ-(Aryl,Styryl)-β-hydroxy Acids and Highly Substituted Tetrahydrofurans
Journal of the American Chemical Society, 2016Co-Authors: Jothi L Nallasivam, Rodney A FernandesAbstract:An efficient palladium-catalyzed site-selective arylation of γ-vinyl-γ-lactone by aryl boronic acid has been developed. γ-Vinyl-γ-lactone 1a has been contemplated as allyl electrophile donor for allylic arylation via π-allyl palladium intermediate using 1.5 equiv of aryl boronic acid 2. Using 3.0 equiv of the latter resulted in mono-arylation by allylic substitution and subsequent site-selective second arylation by directed allylic C–H activation giving stereoselectively anti-γ-(aryl,styryl)-β-hydroxy acids. Presence of O2 was crucial for the second arylation via Pd(II) catalysis. Thus, a good synergy of dual catalysis by Pd(0) and Pd(II) was observed. This methodology has been elaborated to synthesize highly substituted tetrahydrofurans including aryl-Hagen’s gland lactone analogues via intramolecular Iodoetherification.
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Pd-Catalyzed Site-Selective Mono-allylic Substitution and Bis-arylation by Directed Allylic C–H Activation: Synthesis of anti-γ-(Aryl,Styryl)-β-hydroxy Acids and Highly Substituted Tetrahydrofurans
2016Co-Authors: Jothi L Nallasivam, Rodney A FernandesAbstract:An efficient palladium-catalyzed site-selective arylation of γ-vinyl-γ-lactone by aryl boronic acid has been developed. γ-Vinyl-γ-lactone 1a has been contemplated as allyl electrophile donor for allylic arylation via π-allyl palladium intermediate using 1.5 equiv of aryl boronic acid 2. Using 3.0 equiv of the latter resulted in mono-arylation by allylic substitution and subsequent site-selective second arylation by directed allylic C–H activation giving stereoselectively anti-γ-(aryl,styryl)-β-hydroxy acids. Presence of O2 was crucial for the second arylation via Pd(II) catalysis. Thus, a good synergy of dual catalysis by Pd(0) and Pd(II) was observed. This methodology has been elaborated to synthesize highly substituted tetrahydrofurans including aryl-Hagen’s gland lactone analogues via intramolecular Iodoetherification
Jothi L Nallasivam - One of the best experts on this subject based on the ideXlab platform.
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pd catalyzed site selective mono allylic substitution and bis arylation by directed allylic c h activation synthesis of anti γ aryl styryl β hydroxy acids and highly substituted tetrahydrofurans
Journal of the American Chemical Society, 2016Co-Authors: Jothi L Nallasivam, Rodney A FernandesAbstract:An efficient palladium-catalyzed site-selective arylation of γ-vinyl-γ-lactone by aryl boronic acid has been developed. γ-Vinyl-γ-lactone 1a has been contemplated as allyl electrophile donor for allylic arylation via π-allyl palladium intermediate using 1.5 equiv of aryl boronic acid 2. Using 3.0 equiv of the latter resulted in mono-arylation by allylic substitution and subsequent site-selective second arylation by directed allylic C–H activation giving stereoselectively anti-γ-(aryl,styryl)-β-hydroxy acids. Presence of O2 was crucial for the second arylation via Pd(II) catalysis. Thus, a good synergy of dual catalysis by Pd(0) and Pd(II) was observed. This methodology has been elaborated to synthesize highly substituted tetrahydrofurans including aryl-Hagen’s gland lactone analogues via intramolecular Iodoetherification.
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Pd-Catalyzed Site-Selective Mono-allylic Substitution and Bis-arylation by Directed Allylic C–H Activation: Synthesis of anti-γ-(Aryl,Styryl)-β-hydroxy Acids and Highly Substituted Tetrahydrofurans
Journal of the American Chemical Society, 2016Co-Authors: Jothi L Nallasivam, Rodney A FernandesAbstract:An efficient palladium-catalyzed site-selective arylation of γ-vinyl-γ-lactone by aryl boronic acid has been developed. γ-Vinyl-γ-lactone 1a has been contemplated as allyl electrophile donor for allylic arylation via π-allyl palladium intermediate using 1.5 equiv of aryl boronic acid 2. Using 3.0 equiv of the latter resulted in mono-arylation by allylic substitution and subsequent site-selective second arylation by directed allylic C–H activation giving stereoselectively anti-γ-(aryl,styryl)-β-hydroxy acids. Presence of O2 was crucial for the second arylation via Pd(II) catalysis. Thus, a good synergy of dual catalysis by Pd(0) and Pd(II) was observed. This methodology has been elaborated to synthesize highly substituted tetrahydrofurans including aryl-Hagen’s gland lactone analogues via intramolecular Iodoetherification.
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Pd-Catalyzed Site-Selective Mono-allylic Substitution and Bis-arylation by Directed Allylic C–H Activation: Synthesis of anti-γ-(Aryl,Styryl)-β-hydroxy Acids and Highly Substituted Tetrahydrofurans
2016Co-Authors: Jothi L Nallasivam, Rodney A FernandesAbstract:An efficient palladium-catalyzed site-selective arylation of γ-vinyl-γ-lactone by aryl boronic acid has been developed. γ-Vinyl-γ-lactone 1a has been contemplated as allyl electrophile donor for allylic arylation via π-allyl palladium intermediate using 1.5 equiv of aryl boronic acid 2. Using 3.0 equiv of the latter resulted in mono-arylation by allylic substitution and subsequent site-selective second arylation by directed allylic C–H activation giving stereoselectively anti-γ-(aryl,styryl)-β-hydroxy acids. Presence of O2 was crucial for the second arylation via Pd(II) catalysis. Thus, a good synergy of dual catalysis by Pd(0) and Pd(II) was observed. This methodology has been elaborated to synthesize highly substituted tetrahydrofurans including aryl-Hagen’s gland lactone analogues via intramolecular Iodoetherification
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Pd-Catalyzed Site-Selective Mono-allylic Substitution and Bis-arylation by Directed Allylic C-H Activation: Synthesis of anti-gamma-(Aryl,Styryl)-beta-hydroxy Acids and Highly Substituted Tetrahydrofurans
'American Chemical Society (ACS)', 2016Co-Authors: Jothi L Nallasivam, Ra FernandesAbstract:An efficient palladium-catalyzed site-selective arylation of gamma-vinyl-gamma-lactone by aryl boronic acid has been developed. gamma-Vinyl-gamma-lactone la has been contemplated as allyl electrophile donor for allylic arylation via pi-allyl palladium intermediate using 1.5 equiv of aryl boronic acid 2. Using 3.0 equiv of the latter resulted in mono-arylation by allylic substitution and subsequent site-selective second arylation by directed allylic C-H activation giving stereoselectively anti-gamma-(aryl,styryl)-beta-hydroxy acids. Presence of O-2 was crucial for the second arylation via Pd(II) catalysis. Thus, a good synergy of dual catalysis by Pd(0) and Pd(II) was observed. This methodology has been elaborated to synthesize highly substituted tetrahydrofurans including aryl-Hagen's gland lactone analogues via intramolecular Iodoetherification
Shigefumi Kuwahara - One of the best experts on this subject based on the ideXlab platform.
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Total Synthesis of Amphirionin-4
Organic Letters, 2016Co-Authors: Yusuke Ogura, H. Sato, Shigefumi KuwaharaAbstract:An expeditious enantioselective total synthesis of amphirionin-4, a remarkably potent promoter of the proliferation of ST-2 cells, has been achieved from (±)-(E)-1,4-hexadien-3-ol by an 8-pot sequence that features the Sharpless kinetic resolution, Iodoetherification, and the CBS reduction to install the stereocenters, utilization of four one-pot transformations to streamline the synthetic process, and the Stille coupling reaction at nearly the center of the target molecule to complete the total synthesis.
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Total Synthesis of Amphirionin‑4
2016Co-Authors: Yusuke Ogura, H. Sato, Shigefumi KuwaharaAbstract:An expeditious enantioselective total synthesis of amphirionin-4, a remarkably potent promoter of the proliferation of ST-2 cells, has been achieved from (±)-(E)-1,4-hexadien-3-ol by an 8-pot sequence that features the Sharpless kinetic resolution, Iodoetherification, and the CBS reduction to install the stereocenters, utilization of four one-pot transformations to streamline the synthetic process, and the Stille coupling reaction at nearly the center of the target molecule to complete the total synthesis
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Synthesis of macrotetrolide α, a designed polynactin analog composed of bishomononactic acids
Tetrahedron, 2011Co-Authors: Kentaro Takai, Shigefumi Kuwahara, Tadaatsu Hanadate, Masaki Abe, Yukie Ono, Teiko Yamada, Hiromasa KiyotaAbstract:Macrotetrolide α (1), a designed polynactin analog composed of (+)- and (−)-bishomononactic acids, was synthesized. The monomeric acids were prepared using cis-selective Iodoetherification and optical resolution of the corresponding O-acetylmandelates as the key steps. Esterification and macrolactonization of the monomers were performed by Corey–Mukaiyama–Gerlach method. Compound 1 showed no immunosuppressive activity contrary to other natural polynactin congeners.
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Synthesis of the L‐Acid (C1–C18) Fragment of Pamamycin‐593 and De‐N‐methylpamamycin‐579
European Journal of Organic Chemistry, 2008Co-Authors: Ayako Miura, Yukito Furuya, Shigefumi Kuwahara, Shin Ya Takigawa, Yusuke Yokoo, Hiromasa KiyotaAbstract:The L-acid (C1–C18) fragment of pamamycin-593 and de-N-methylpamamycin-579, strong aerial mycelium-inducers of Streptomyces alboniger, was synthesized using a cis-selective Iodoetherification and a nucleophilic addition of a cerium acetylide to an aldehyde as the key steps. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
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Synthesis of southern (C1′–C11′) fragment of pamamycin-635A
Tetrahedron, 2005Co-Authors: Ayako Miura, Hiromasa Kiyota, Shigefumi KuwaharaAbstract:Abstract The synthesis of the southern (C1′–C11′) fragment of pamamycin-635A, isolated from Streptomyces alboniger , was achieved via an Evans aldol reaction, a cis -selective Iodoetherification and a stereospecific deiodination as the key steps.
Darrin Dabideen - One of the best experts on this subject based on the ideXlab platform.
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Olefin metathesis-Iodoetherification-dehydroiodination strategy for spiroketal subunits of polyether antibiotics.
The Journal of Organic Chemistry, 2009Co-Authors: Kurissery A. Tony, Darrin Dabideen, Maria Dolores Díaz-hernández, Jesús Jiménez-barbero, David R. MootooAbstract:The convergent synthesis of two pentacyclic analogues of the polyether monensin A is described. Although different with respect to the configuration of the alcohol at the 3 position of the six-membered ring of the spiroketal subunit, the configuration at the acetal center in both structures is unchanged and is consistent with the anomeric effect. The key synthetic steps are the coupling of two complex segments via an olefin metathesis, and the subsequent conversion of a dihydroxyalkene to the spiroketal through an Iodoetherification−dehydroiodination sequence. The compatibility of these transformations with a variety of functional groups makes the overall strategy appropriate for highly substituted frameworks.
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an Iodoetherification dehydroiodination strategy for the synthesis of complex spiroketals from dihydroxyalkene precursors
Organic and Biomolecular Chemistry, 2008Co-Authors: Kurissery A. Tony, Darrin Dabideen, David R. MootooAbstract:Dihydroxyalkenes or their monoprotected alcohol derivatives are transformed to 5,5- and 5,6-spiroketals through a sequence involving an initial iodocyclization, followed by a silver triflate mediated spiroketalization step on the derived hydroxy-iodoether.
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An Iodoetherification–dehydroiodination strategy for the synthesis of complex spiroketals from dihydroxyalkene precursors
Organic & Biomolecular Chemistry, 2008Co-Authors: Kurissery A. Tony, Darrin Dabideen, David R. MootooAbstract:Dihydroxyalkenes or their monoprotected alcohol derivatives are transformed to 5,5- and 5,6-spiroketals through a sequence involving an initial iodocyclization, followed by a silver triflate mediated spiroketalization step on the derived hydroxy-iodoether.
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Highly functionalized trans-2,5-disubstituted tetrahydrofurans from ribofuranoside templates: precursors to linked polycyclic ethers☆
Tetrahedron Letters, 2003Co-Authors: Darrin Dabideen, David R. MootooAbstract:Iodoetherification of C5 allylated ribo-furanosides leads to trans-2,5-disubstituted tetrahydrofurans with high selectivity. The application of this reaction to the synthesis of complex polycyclic ethers is illustrated in the preparation of a truncated, tricyclic analog of monensin A.
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PYRANOSIDE ALKENE TEMPLATES FOR THE SYNTHESIS OF CIS-2,5-DISUBSTITUTED TETRAHYDROFURAN SUBUNITS OF THE ACETOGENINS
Journal of Carbohydrate Chemistry, 2002Co-Authors: Huiping Zhang, Darrin Dabideen, Galyna Pushchinska, David R. MootooAbstract:The Iodoetherification reaction of t-butyl and trityl glycosides of C6 allylated-2,3-dideoxy-d-erythro- and d-threo-pyranosides was examined as part of a model study aimed at the synthesis of the 2,5-disubstituted tetrahydrofuran subunits found in the acetogenin group of natural products. In general, the t-butyl glycosides gave moderate, and the trityl derivatives, excellent stereoselectivity for the cis THF product.
