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Showing 1 to 20 of 31 for “"Enynes"”.
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Intramolecular [4+2] cycloadditions of conjugated enynes : scope and mechanism
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1996.
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Intramolecular [4 + 2] cycloadditions of conjugated enynes with highly strained cyclic alkenes
… [4 + 2] cycloadditions of conjugated enynes with cyclopropenes. A new [4 + 4] annulation method has been developed for the synthesis of eight-membered carbocycles involving cycloadditions of cyclobutenones with conjugated enynes.
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Synthesis of heterocyclic compounds via intramolecular [4+2] cycloadditions of conjugated enynes
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1997.
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Mechanistic and synthetic studies of the intramolecular [4+2] cycloaddition of conjugated enynes
… intramolecular [4+2] cycloaddition of conjugated enynes has shown the reaction likely proceeds by a concerted cycloaddition of the enyne to give a highly reactive cyclic allene intermediate which isomerizes to aromatic and dihydroaromatic compounds through proton transfer or hydrogen atom transfer …
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Nickel-catalyzed reductive coupling reactions of 1,6-enynes and the total synthesis of (+)-acutiphycin
… Coupling Reactions of Aldehydes and Chiral 1,6-Enynes. A study of nickel-catalyzed reductive coupling reactions of aldehydes and chiral 1,6-enynes has provided evidence for stereospecific ligand substitution from a planar three-coordinate nickel species as a plausible explanation of …
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Cationic Carbocyclisation reactions of Alkynols and enynes for the synthesis of cyclic alkenyl halides and triflates
La reactividad de 1,5-alquinoles y 1,5-eninos en el contexto de reacciones de carbociclación catiónica promovidas por ácidos de Brønsted y Lewis ha sido estudiada y consecuentemente se ha encontrado un comportamiento de los citados sistemas sin precedentes en la bibliografía. En términos generales, …
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Transition-metal catalysis of cyclocarbonylation and cycloisomerization reactions
… Pauson-Khand cyclization of nitrogen-containing enynes using carbon monoxide and a catalytic amount of (EBTHI)TiMe2 was examined. The influence of the nitrogen substituent and the concentration of the catalyst on the enantioselectivity of this cyclization was explored. It has been found that …
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Nickel-catalyzed reductive coupling reactions : application to the total syntheses of pumiliotoxins 209F and 251D
Catalytic Asymmetric Reductive Coupling of 1,3-Enynes and Aromatic Aldehydes Nickel-catalyzed reductive coupling reactions of 1,3-enynes and aromatic aldehydes efficiently afford conjugated dienols in excellent regioselectivity and modest enantioselectivity. These reactions were conducted in the …
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Studies directed toward the synthesis of the B-type amphidinolide natural products using nickel-catalyzed reductive couplings of enynes and carbonyl compounds
Progress coupling of substrates, toward the total synthesis of amphidinolide B1 is described. The reductive 1,3-eynes and ketones was explored. It was found to work well with simple but failed to yield intermediates toward amphidinolide B1 [images] ... The coupling of 1,3-enyne and aldehyde …
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Synthesis of indolines and indoles via intramolecular [4 + 2] cycloaddition of ynamides and conjugated enynes ; Synthesis of nitrogen heterocycles in supercritical carbon dioxide
… alkynyl halide. Ynamides react with conjugated enynes in intramolecular [4 + 2] cycloaddition to afford substituted indolines that undergo oxidation with o-chloranil to furnish the corresponding indoles. The cycloaddition substrates are easily assembled from derivatives of 3-butynylamine by …
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Fused Heterocycles as Spinster Homolog 2 Inhibitors and Regio- and Stereoselective Copper-Catalyzed Borylation-Protodeboronation of 1,3-Diynes: Access to (Z)-1,3-Enynes
… and stereoselective reactions. Conjugated 1,3-enynes are important functional groups that iii are found in active natural products, organic synthetic intermediates, and materials. Previous methods used rare transition metals, designer ligands, or harsh acidic conditions to synthesize such …
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Selective, nickel-catalyzed carbon-carbon bond-forming reactions of alkynes
… nickel-catalyzed reductive couplings of 1,3-enynes with aldehydes and epoxides, the conjugated alkene dramatically enhances reactivity and uniformly directs regioselectivity, independent of the nature of the other alkyne substituent (aryl, alkyl (1°, 2°, 3°)) or the degree of alkene …
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The Development of Sequential Silylcarbocyclization Silicon-Based Cross -Coupling Reactions and Their Application in the Total Synthesis of Isodomoic Acid H
… rhodium-catalyzed silylcarbocyclization of enynes parlayed with a palladium-catalyzed, silicon-based cross-coupling reaction has been developed. 1,6-Enynes reacted with benzyldimethylsilane in the presence of rhodium catalysts to afford five-membered rings bearing a …
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The Development of Sequential Silylcarbocyclization Silicon-Based Cross-Coupling Reactions and Their Application in the Total Synthesis of Isodomoic Acid H
… rhodium-catalyzed silylcarbocyclization of enynes parlayed with a palladium-catalyzed, silicon-based cross-coupling reaction has been developed. 1,6-Enynes reacted with benzyldimethylsilane in the presence of rhodium catalysts to afford five-membered rings bearing a …
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Copper(I) Hydride-Catalyzed Transformations of π-Electrophiles
… Amines by CuH-Catalyzed Coupling of Imines and Enynes A novel method for the synthesis of chiral homopropargylic amines is detailed. Aromatic and aliphatic N-phosphinoyl aldimines possessing a variety of functional groups are coupled with both terminal and internal enynes under mild conditions. …
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Diastereoselective nickel-catalyzed reductive coupling of alkynes and aldehydes and application towards the B-type amphidinolides
… reductive coupling reaction of 1,3-enynes and aldehydes was found to be a very effective way of installing the congested 1,3-diene moiety common to all members of this class of natural products. This methodology was further examined as a fragment coupling strategy for the syntheses …
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Cascade Transformations in Organic Synthesis: I. The Interception of Carbene Alkyne Metathesis Intermediates II. Photo-Activation of Hydrazones III. Organocatalyzed Cascade Conjugate Addition/Aldol Annulation of Organoboronates
… mechanism converts those triazoles to spiro-1,3-enynes. Several different termination pathways were designed to achieve the formal 6-exo-dig and formal 7-endo-dig cyclization. Third, a light-promoted Barluenga-Valdés coupling was developed. Many different diarylalkanes and triarylboronates could …
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Organomanganese compounds in organic synthesis
… pentacarbonyl-mediated transformation of enynes to cyclopropanated bicyclic compounds and cyclopentanes bearing an exocyclic double bond. In the current study, benzylmanganese pentacarbonyl was used instead of methylmanganese pentacarbonyl under similar conditions. In the current study …
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