Cascade Cyclizations and Couplings Involving Nickel Enolates

Mahandru, Gireesh M.; Skauge, Andy R. L.; Chowdhury, Sanjoy K.; Amarasinghe, Kande K. D.; Heeg, Mary Jane; Montgomery, John

doi:10.1021/ja037423w

Cited by 63 publications

(21 citation statements)

References 55 publications

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“…Further synthetic applications of the proposed nickel metallacycle and related metallacycles that are beyond the scope of this Review have also been reported. [23] An alternate mechanism for this class of transformations has been discussed. If the reaction is initiated by Lewis acid promoted oxidative addition of nickel(0) to the enone, then pallyl intermediate 21 would result (Scheme 11).…”

Section: Couplings Of Alkenes With Alkynesmentioning

confidence: 99%

Nickel‐Catalyzed Reductive Cyclizations and Couplings

2004

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For over 50 years, nickel catalysis has been applied in cycloaddition processes. Nickel-catalyzed reductive couplings and cyclizations, however, have only recently attracted a high level of interest. This group of new reactions allows a broad range of multicomponent couplings involving two or more pi components with a main-group or transition-metal reagent. These processes allow the assembly of important organic substructures from widely available reaction components. Multiple contiguous stereocenters, polycyclic ring systems, and novel arrays of complex functionality may often be prepared from simple, achiral, acyclic precursors. With three or more reactive functional groups participating in the catalytic processes, many mechanistic questions abound, including the precise timing of bond constructions and the nature of reactive intermediates. This Review is thus aimed at providing a critical evaluation of recent progress in this rapidly developing field.

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Section: Couplings Of Alkenes With Alkynesmentioning

confidence: 99%

Nickel‐Catalyzed Reductive Cyclizations and Couplings

2004

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“…83 Spirocycle 257 can be synthesized from a simple acyclic precursor using nickel(0) as a catalyst. 84 . When the phenolic group of the starting stilbene is protected, such as methoxylated catechol 258b, then the reaction stops at the quinone stage (i.e., 259b) which further supports the rearrangement mechanism.…”

Section: Oxidative Cyclization Methodsmentioning

confidence: 99%

Selected Synthetic Strategies to Spirocyclics

Kotha¹,

Deb²,

Lahiri³

et al. 2009

Synthesis

290

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“…Enol-alkyne reductive cycloadditions [253,254] are also the [3 + 2] cycloadditions. For example, the intramolecular cyclization of the enol-alkyne proceeds in the presence of a nickel catalyst to give a tricyclic single diastereomer in 71% yield, as shown in eqn (27).…”

Section: Azide Alkyne Huisgen Cycloaddition R Copper Catalystsmentioning

confidence: 99%

“…For example, the intramolecular cyclization of the enol-alkyne proceeds in the presence of a nickel catalyst to give a tricyclic single diastereomer in 71% yield, as shown in eqn (27). [254] Monosubstituted conjugated enynes smoothly undergo [4 + 2] homodimerization by the cyclization of the enyne and monoyne cyclization in the presence of palladium catalyst to give styrene derivatives as shown in eqn (28). [255] These [4 + 2] cycloadditions also proceed by the diene and monoyne cycloaddition, [256 -258] and by the enyne and diyne cycloaddition.…”

Section: Azide Alkyne Huisgen Cycloaddition R Copper Catalystsmentioning

confidence: 99%

Three characteristic reactions of alkynes with metal compounds in organic synthesis

Omae

2008

Applied Organom Chemis

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IntroductionBoth alkynes and alkenes are compounds having at least one π -electron bond. Therefore, in these compounds, reactions such as the addition of hydrogen, the addition of halogens, the addition of hydrogen halides, metathesis, oxidation and polymerization, proceed in the presence of metal compounds.However, alkynes have another set of π -electron bonds. These two sets of π -electron bonds in alkynes are mutually orthogonal. Hence, the reactions of alkynes in the presence of the metal compounds are different from the reactions of alkenes.As described in the next section, the two sets of mutually orthogonal π -electron bonds tend to easily bond with d-electrons in transition metals. Consequently, the characteristic reactions of alkynes occur in the presence of the transition metals. In these transition metal compounds, especially, a Co-Co bond in (CO) 4 Co-Co(CO) 4 , very easily form a mutually bridged bond with the two sets of π -electron bonds in alkynes. These reactions of alkynes with alkenes in the presence of Co 2 (CO) 8 are the most characteristic reactions of alkynes with the transition metals in organic synthesis.This first type of characteristic reaction of alkynes with organocobalt compounds is the Pauson-Khand reactions. Reactions that are similar to the Pauson-Khand reactions, Pauson-Khand-type reactions, occur in the presence of the other transition metal compounds besides the cobalt carbonyl compounds, and also proceed as the first type of characteristic reactions. The Pauson-Khand reactions and Pauson-Khand-type reactions are the reactions of alkynes, alkenes and carbon monoxide. In these three components, alkynes and carbon monoxide have two sets of π -electron bonds and alkenes have one set of π -electron bond. These reactions are also called as the [2 + 2 + 1] cyclizations.The second type of characteristic reactions of alkynes with the transition metal compounds is other cyclizations in which alkynes react with compounds having π -electron bonds such as other alkynes, alkenes, allenes, aldehydes, ketones, imines, carbon monoxide, carbon dioxide and nitriles. These reactions are cyclooligomerizations and cycloadditions.The third type of characteristic reaction of alkynes in the presence of the metal compounds is coupling reactions in which the negative charge of the carbon atom in alkynes is involved in addition to the high reactivity to the π -electron bond. The reactions are carbonylations, dioxycarbonylations, coupling reactions with aldehydes, ketones, imines, alkenes, allyl compounds, alkynes, other oxygen-containing compounds or nitrogen-containing compounds, Sonogashira reactions and other coupling reactions.The characteristic reactions of alkynes with organocobalt compounds in organic synthesis have been reported in a previous review article. [1] This present review reports mainly on three characteristic reactions of alkynes with the metal compounds in organic synthesis, excluding the organocobalt compounds. * Correspondence to : Iwao Omae, Nihon Pharmaceutical University, 10281 ...

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Cascade Cyclizations and Couplings Involving Nickel Enolates

Cited by 63 publications

References 55 publications

Nickel‐Catalyzed Reductive Cyclizations and Couplings

Nickel‐Catalyzed Reductive Cyclizations and Couplings

Selected Synthetic Strategies to Spirocyclics

Three characteristic reactions of alkynes with metal compounds in organic synthesis

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