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Sazonov, P. K.; Artamkina, G. A.; Beletskaya, I. P.

doi:10.1023/a:1012469516433

Cited by 7 publications

(16 citation statements)

References 9 publications

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“…In the results obtained in the present work and in a series of previous papers [16][17][18][19][20] (Table 3) it was easy to trace a series of fully understandable qualitative relationships. The susceptibility to the halogenophilic reaction increases in the order Cl << Br << I, but the deciding role is played by the structure of the vinyl halide: Stabilization of the carbanionic intermediates of the Ad N E or halogenophilic reactions and the presence steric hindrances for attack by the nucleophile at the double bond.…”

Section: Z-phch=cbr(co 2 Ch 3 ) [16] Halogenophilic (Hme) Z-(cf 3 ) 3supporting

confidence: 63%

“…HME = Halogen-Metal Exchange. [18] Scheme 8 only in reaction with [Re(CO) 5 ]Na but also with [Mn(CO) 5 ]K. [Mn(CO 5 )I and [Re 2 (CO) 9 I]Na were also detected in the reaction products.] In the presence of the "anion trap" its reaction with [Mn(CO) 5 ]K leads quantitatively to the product from protonation of the vinylic carbanion (4-Z-Cl, yield 90%).…”

Section: Z-phch=cbr(co 2 Ch 3 ) [16] Halogenophilic (Hme) Z-(cf 3 ) 3mentioning

confidence: 99%

“…It should, however, be noted that the latter are quite weakly activated to nucleophilic substitution by the Ad N E mechanism. At the same time for a series of activated vinyl chlorides, even perfluorinated, and primary vinyl bromides (PhCCN=CHBr) the normal Ad N E substitution mechanism is realized [18,19].…”

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confidence: 99%

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Halogenophilic and classical Ad N E mechanisms in nucleophilic vinylic substitution reactions involving the anions of transition metal carbonyls

2011

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The mechanism of the reaction of carbonylate anions ([M(CO) n L] -) with highly activated vinyl halides (Hal = Cl, Br, I) was investigated by the method of "anion traps" -the effect of proton donors on the composition of the reaction products. It was demonstrated that the reactions with PhCHal=C(Z) 2 (Hal = Br, I; Z = CN, CO 2 Et) and PhCN=CClI take place through initial attack by the carbonylate at the halogen atom, the reactions with PhCCl=C(CO 2 Et) 2 and PhCOCH=CHHal (Hal = Cl, I) take place through attack by the carbonylate at the ð bond (Ad N E mechanism), and in the case of E-and Z-PhCN=CHI the two mechanisms operate concurrently. The main laws determining the reaction mechanisms are analyzed.Nucleophilicity and nucleophilic substitution are among the most important concepts and processes in organic chemistry. Among the enormous variety of nucleophilic reagents a quite special class is presented by nucleophiles in which the reaction center is localized at a metal atom. The reactivity of such metal-centered anions [1-9] differs fundamentally from that observed in "classical" N-, O-, or S-nucleophiles and is largely not understood. Even in aliphatic substitution reactions metal-centered anions behave unusually, which has in due course stimulated discussion of the mechanism of single-electron transfer (SET) and its relationship with the S N 2 mechanism [10-13].For a number of years the laws governing nucleophilic vinylic and aromatic substitution involving the anions of transition metal carbonyls (carbonylates) -an extensive class of metal-centered anions widely used in synthesis and acting as intermediates in a series of practically important catalytic processes such as the carbonylation of alkyl halides and 350 0040-5760/11/4606-0350 Scheme 1. The addition-elimination mechanism (Ad N E).

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Section: Z-phch=cbr(co 2 Ch 3 ) [16] Halogenophilic (Hme) Z-(cf 3 ) 3supporting

confidence: 63%

Section: Z-phch=cbr(co 2 Ch 3 ) [16] Halogenophilic (Hme) Z-(cf 3 ) 3mentioning

confidence: 99%

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Halogenophilic and classical Ad N E mechanisms in nucleophilic vinylic substitution reactions involving the anions of transition metal carbonyls

2011

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“…Yet, in several other polyfluoroalkenyl chlorides, namely Z-and E-chlorodifluorostyrenes 26,27 and 1-chloro-2-(trifluoromethyl)hexafluorocyclopentene 26 ( Fig. 2), NS with carbonylates follows "normal" Ad N E pathway (Scheme 3).…”

Section: Resultsmentioning

confidence: 99%

“…Experiments with polyfluorinated aryl and vinyl halides have been described previously. [21][22][23]26 [CpFe(CO) 2 ]K was obtained quantitatively (95-98%) by reductive cleavage of the dimer [CpFe(CO) 2 ] 2 with excess of NaK 2.8 alloy (0.10-0.15 ml per 1 mmol of dimer). 33 [Re(CO) 5 ]Na was prepared by the reduction of Re 2 (CO) 10 with 0.5% NaHg (30-50% excess) and purified by the low temperature crystallisation from THF.…”

Section: Methodsmentioning

confidence: 99%

Metal carbonyl anions as model metal-centered nucleophiles in aromatic and vinylic substitution reactions

Sazonov¹,

Ivushkin²,

Artamkina³

et al. 2003

Arkivoc

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Carbonylmetallates—A Special Family of Nucleophiles in Aromatic and Vinylic Substitution Reactions

Sazonov

Beletskaya

2016

Chemistry A European J

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Carbonylmetallates, [M(CO)(n)L](-), anionic transition-metal carbonyl complexes, represent a large family of metal-centered nucleophiles, and studying carbonylmetallates allows us to understand the differences in the behavior of the metal-centered complexes versus heteroatom-based nucleophiles. The mechanisms of carbonylmetallate reactions with aryl- and alkenyl halides have been examined by employing radical and, especially, carbanion trapping techniques. Carbonylmetallates show a marked preference for halogenophilic attack, and nucleophilic substitution with carbonylmetallates is often not a direct process, but proceeds through the initial attack at halogen with subsequent coupling of carbanion and HalM(CO)(n)L intermediates. Factors governing the competition between the halogenophilic and more common "carbophilic" reaction pathways, as well as the means of predicting the actual course of reaction are discussed. The review also considers other aspects of carbonylmetallate reactivity, including ion-pairing effects, radical-mediated nucleophilic substitution pathways, and the carbonylmetallate nucleophilicity scale in the reactions with π-electrophiles.

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Cited by 7 publications

References 9 publications

Halogenophilic and classical Ad N E mechanisms in nucleophilic vinylic substitution reactions involving the anions of transition metal carbonyls

Halogenophilic and classical Ad N E mechanisms in nucleophilic vinylic substitution reactions involving the anions of transition metal carbonyls

Metal carbonyl anions as model metal-centered nucleophiles in aromatic and vinylic substitution reactions

Carbonylmetallates—A Special Family of Nucleophiles in Aromatic and Vinylic Substitution Reactions

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