Nickel-Catalyzed Cyclizations and Couplings with Vinylzirconium Reagents

Ni, Yi; Amarasinghe, Kande K. D.; Montgomery, John

doi:10.1021/ol025812+

Cited by 88 publications

(34 citation statements)

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“…Intramolecular versions of this process, largely developed in our laboratories, have been demonstrated with organozinc reagents (as in the production of 7 and 8), [13] organoaluminum reagents, [14] and alkenyl zirconium reagents (as in the production of 9, Scheme 4). [15] Both internal and terminal alkynes are cleanly tolerated as the acetylenic component, and enones, alkylidene malonates, nitroalkenes, and unsaturated imides are tolerated as the electron-deficient alkene component. The scope of the reaction is very broad (Scheme 4).…”

Section: Couplings Of Alkenes With Alkynesmentioning

confidence: 99%

“…To avoid this limitation and to expand the scope of readily available alkenyl units, we examined the addition of alkenyl zirconium reagents in both intra-(e.g., 42) and intermolecular (e.g., 43) additions (Scheme 20). [15] Both processes proceed efficiently and avoid many of the limitations derived from the high reactivity of alkenyl zinc reagents. However, a surprising observation in the intermolecular couplings is that a regio- …”

Section: Coupling Of Carbonyl Compounds or Imines With Alkynesmentioning

confidence: 99%

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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%

Section: Coupling Of Carbonyl Compounds or Imines With Alkynesmentioning

confidence: 99%

Nickel‐Catalyzed Reductive Cyclizations and Couplings

2004

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“…However, alkenylzirconium reducing agents, derived from hydrozirconation of alkynes, participated in both inter -and intra -molecular coupling reactions without suffering competing addition to the carbonyl (Scheme 8.16 ) [21] . This methodology provides a facile entry to functionalized cyclic or acyclic 1,3 -dienes, and expands the generality of the multicomponent coupling to include the introduction of sp 2 -hybridized centers from the reducing agent.…”

Section: Three -Component Couplings Via Alkyl Group Transfer -Methods mentioning

confidence: 99%

Nickel‐Catalyzed Reductive Couplings and Cyclizations

Malik

Baxter

Montgomery

2010

Catalysis Without Precious Metals

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Many classes of standard organic transformations involve the coupling or cycloaddition of two different π -components to assemble a more functionalized product. Many such processes are amenable to the union of two complex fragments, thus allowing convergent approaches to complex organic molecules. Diels -Alder cycloadditions, Prins addition reactions, and ene reactions are examples of broadly useful processes that involve the union of two π -components in a selective manner. As a complement to these classical transformations, the reductive coupling of two π -components provides an alternative strategy for assembly of complex fragments from the same types of starting materials [1 -8] . Whereas the starting components resemble those required for the types of standard organic transformations noted above, the products obtained differ structurally and are obtained in a reduced oxidation state based on the action of the reducing agent employed.A number of transition metal catalyst/reducing agent combinations are known to promote various reductive coupling processes. In addition to the nickelcatalyzed variants that are the subject of this chapter, important advances have been made with titanium -[9 -13] , iridium - [14] , and rhodium -catalyzed variants [15] . Many reducing agents have been employed, and the most widely used classes include silanes, organozincs, organoboranes, molecular hydrogen, and alcohols. The specifi c focus of this chapter will be the development of nickel -catalyzed reductive couplings and cyclizations between a polar π -component and a non -polar π -component. This strategy allows the two π -components to be differentiated in catalytic reactions, and thus avoids homocoupling processes that are often problematic in transformations of this type. The use of either aldehydes or α , β -unsaturated carbonyls as the polar component, and alkynes as the non -polar component has been a primary focus of our laboratories and will be the subject of this chapter. Extensive related developments involving dienes as the non -polar component reported by the laboratories of Mori [16] , Sato [17] , and Tamaru [18] have been reviewed elsewhere [3] and will not be extensively discussed in this 8 Catalysis Without Precious Metals. Edited by R. Morris Bullock

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“…The reaction is quite general and useful for the construction of spiro compounds, bicyclic compounds and monocyclic compounds with stereochemically defined double bonds [71,72]. The last example demonstrates that alkenylzirconiums, being readily prepared by hydrozirconation of terminal alkynes, can be utilized to the reaction in the presence of ZnCl 2 .…”

Section: Sequential Reaction With Enonesmentioning

confidence: 98%

Reaction of Alkynes

Ikeda

2005

Modern Organonickel Chemistry

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Since the earliest investigations represented by cycloaddition [1] and carboxylation [2], the nickel-catalyzed reactions of alkynes have been extensively studied by many research groups. This chapter highlights recent developments in the nickelcatalyzed reactions of alkynes. Recent advancements in cycloaddition and the carboxylation of alkynes are described in Chapters 6 and 7, respectively.The most extensively studied reaction is the addition reaction of an AaB species (e.g., HaH, H-metals, metals-metals, CaH, and C-metals, where metals ¼ Si, Sn, B, etc.) to alkynes (Scheme 4.1). Generally, the addition of an AaB species to alkynes starts with oxidative addition of the AaB species to a nickel(0) complex to generate an AaNiaB species (see Section 1.7.1). The insertion of an alkyne into either the AaNi or the BaNi bond gives the alkenylnickel intermediate(s), which undergo reductive elimination to produce the alkenes functionalized with an A and B functionalities at the 1,2-positions (see Section 1.7.4). The A and B groups are usually introduced on the same face of alkynes, and cis-alkenes with respect to A and B are produced. When an AaB is CaX (X ¼ halogens, O, N), the alkenylnickel X intermediates are capable of undergoing, instead of reductive elimination, Modern Organonickel Chemistry. Edited by Y. Tamaru

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Nickel-Catalyzed Cyclizations and Couplings with Vinylzirconium Reagents

Cited by 88 publications

References 29 publications

Nickel‐Catalyzed Reductive Cyclizations and Couplings

Nickel‐Catalyzed Reductive Cyclizations and Couplings

Nickel‐Catalyzed Reductive Couplings and Cyclizations

Reaction of Alkynes

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