C–C Bond Formation (Part 1) by Addition Reactions: through Carbometallation Catalyzed by Group 8–11 Metals

Fensterbank, Louis; Goddard, Jean‐Philippe; Malacrìa, Max

doi:10.1016/b0-08-045047-4/00129-1

Cited by 7 publications

(2 citation statements)

References 385 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…β-Hydrogen elimination is also involved in many catalytic processes that occur through transition metal enolate complexes as either a productive step or a step that can form side products. For example, β-hydrogen elimination from enolate complexes is a productive step of processes such as Saegusa oxidations of silyl enol ethers and Mizoroki−Heck reactions of acrylates, , whereas it is a possible unproductive side reaction of processes such as transition metal-catalyzed α-arylations , and conjugate additions of organoboranes to enones. , Although the mechanisms of the decompositions of metal alkyl complexes have been studied in detail, much less information has been gained on the rates and mechanism of the decomposition of transition metal enolate complexes. With few exceptions, , published studies on the structure and stability of transition metal enolate complexes have involved those that lack β-hydrogens. , Such complexes are rarely the types of enolate species involved in the catalytic processes described above.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic Study of β-Hydrogen Elimination from Organoplatinum(II) Enolate Complexes

Alexanian

Hartwig

2008

J. Am. Chem. Soc.

View full text Add to dashboard Cite

A detailed mechanistic investigation of the thermal reactions of a series of bisphosphine alkylplatinum(II) enolate complexes is reported. The reactions of methylplatinum enolate complexes in the presence of added phosphine form methane and either free or coordinated enone, depending on the steric properties of the enone. Kinetic studies were conducted to determine the relationship between the rates and mechanism of β-hydrogen elimination from enolate complexes and the rates and mechanism of β-hydrogen elimination from alkyl complexes. The rates of reactions of the enolates were inversely dependent on the concentration of added phosphine, indicating that β-hydrogen elimination from the enolate complexes occurs after reversible dissociation of a phosphine. A normal, primary kinetic isotope effect was measured, and this effect was consistent with ratelimiting β-hydrogen elimination or C-H bond-forming reductive elimination to form methane. Reactions of substituted enolate complexes were also studied to determine the effect of the steric and electronic properties of the enolate complexes on the rates of β-hydrogen elimination. These studies showed that reactions of the alkylplatinum enolate complexes were retarded by electron-withdrawing substituents on the enolate and that reactions of enolate complexes possessing alkyl substituents at the β-position occurred at rates that were similar to those of complexes lacking alkyl substituents at this position. Despite the trend in electronic effects on the rates of reactions of enolate complexes and the substantial electronic differences between an enolate and an alkyl ligand, the rates of decomposition of the enolate complexes were similar to those of the analogous alkyl complexes. To the extent that the rates of reaction of the two types of complex are different, those involving β-hydrogen elimination from the enolate ligand were faster. A difference between the identity of the rate-determining step for decomposition of the two classes of complexes and an effect of stereochemistry on the selectivity for β-hydrogen elimination are possible origins of the observed phenomena.

show abstract

Section: Introductionmentioning

confidence: 99%

Mechanistic Study of β-Hydrogen Elimination from Organoplatinum(II) Enolate Complexes

Alexanian

Hartwig

2008

J. Am. Chem. Soc.

View full text Add to dashboard Cite

show abstract

“…The possibility of extending an organic structure through the formation of new C-C bonds is essential for medicinal chemistry, synthesis of natural products, materials chemistry and even agrochemical synthesis, among others [12][13][14]. Synthetic methodologies via carbometallation have been intensively developing in recent decades, and group 8-11 metals stand out in these transformations [15].…”

Section: C-c Bond Formationmentioning

confidence: 99%

C-H Activation/Functionalization via Metalla-Electrocatalysis

Martins¹,

Sbei²,

Zimmer³

et al. 2022

Electrocatalysis and Electrocatalysts for a Cleaner Environment - Fundamentals and Applications

View full text Add to dashboard Cite

In conventional methods, C−H activations are largely involved in the use of stoichiometric amounts of toxic and expensive metal & chemical oxidants, conceding the overall sustainable nature. Meanwhile, undesired byproducts are generated, that is problematic in the scale up process. However, electrochemical C−H activation via catalyst control strategy using metals as mediators (instead electrochemical substrate control strategy) has been identified as a more efficient strategy toward selective functionalizations. Thus, indirect electrolysis makes the potential range more pleasant, and less side reactions can occur. Herein, we summarize the metalla-electrocatalysis process for activations of inert C−H bonds and functionalization. These Metalla-electrocatalyzed C−H bond functionalizations are presented in term of C−C and C−X (X = O, N, P and halogens) bonds formation. The electrooxidative C−H transformations in the presence of metal catalysts are described by better chemoselectivities with broad tolerance of sensitive functionalities. Moreover, in the future to enhance sustainability and green chemistry concerns, integration of metalla-electrocatalysis with flow and photochemistry will enable safe and efficient scale-up and may even improve reaction times, kinetics and yields.

show abstract

Carboalumination Reactions

Huo

2016

Patai's Chemistry of Functional Groups

View full text Add to dashboard Cite

This chapter deals with the carboalumination of alkenes and alkynes including dienes, diynes, and enynes. The zirconium‐catalyzed methylalumination of alkynes (Negishi ZMA reaction), the zirconium‐catalyzed asymmetric carboalumination of alkenes (Negishi ZACA reaction), and the cyclic carboalumination reactions of alkynes and alkenes (Dzhemilev cyclocarboalumination reaction) are discussed in great detail. The ZMA and ZACA reactions are covered in the following aspects: discovery of the reactions, synthetic methodological developments, mechanistic investigations of the reactions, and their applications in the natural product syntheses. Method developments include improvements on prototypical reactions, further transformations of the carboalumination products, and synergetic coupling of ZMA and ZACA reactions with other synthetic methods, such as palladium‐catalyzed cross‐coupling reactions. Discussion of the cyclic carboalumination is focused on the preparation of aluminacyclopentenes, aluminacyclopentadienes, and aluminacyclopentanes and their further transformations including the preparation of heterocyclic compounds containing N, O, S, Se, P, and B and interesting carbocycles. Recent studies on mechanisms of zirconium‐catalyzed carboalumination with triethylaluminum are described, which reveal multi‐pathway mechanisms leading to either a direct addition of ethyl carbon–metal bond to carbon–carbon multiple bonds or a cyclic carboalumination of alkenes and alkynes. Other metal‐catalyzed or uncatalyzed carboalumination reactions are also covered as appropriate.

show abstract

C–C Bond Formation (Part 1) by Addition Reactions: through Carbometallation Catalyzed by Group 8–11 Metals

Cited by 7 publications

References 385 publications

Mechanistic Study of β-Hydrogen Elimination from Organoplatinum(II) Enolate Complexes

Mechanistic Study of β-Hydrogen Elimination from Organoplatinum(II) Enolate Complexes

C-H Activation/Functionalization via Metalla-Electrocatalysis

Carboalumination Reactions

Contact Info

Product

Resources

About