Dissecting transmetalation reactions at the molecular level: C–B <i>versus</i> F–B bond activation in phenyltrifluoroborate silver complexes

Bathie, Fiona; Stewart, Adam W. E.; Canty, Allan J.; O’Hair, Richard A. J.

doi:10.1039/d0dt03309j

Cited by 7 publications

(2 citation statements)

References 66 publications

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“…As part of ongoing studies examining the mechanistic details of transmetalation reactions in the gas phase , using a combination of mass spectrometry-based methods in conjunction with DFT calculations, , we became interested in studying the reactions of vinyltrimethylsilane with cationic ternary three-coordinate palladium complexes, [(phen)Pd(X)] + , 10 , containing a phenanthroline (phen) ligand and a coordinated halide (X = F or Cl) . These complexes were designed as models of 2 (Scheme A) so that they (i) provide the requisite charge for mass spectrometry experiments; (ii) avoid the Heck manifold by only having a single reactive coordinated (halide) anion (i.e., Ar is deliberately absent); and (iii) have an auxiliary ligand (phen) installed that enforces the reactive cis -geometry.…”

Section: Introductionmentioning

confidence: 99%

Dissecting Transmetalation Reactions at the Molecular Level: Role of the Coordinated Anion in Gas-Phase Models for the Transmetalation Step of the Hiyama Cross-Coupling Reaction

et al. 2021

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Palladium-catalyzed cross-coupling protocols have become a cornerstone in organic synthesis. Here, a gas-phase model of the Hiyama cross-coupling reaction was designed to shed light on the roles of coordinated anions (fluoride versus chloride) in transmetalation from Si to Pd. A combination of mass spectrometry experiments and DFT calculations was used. The ligated palladium fluoride and chloride cationic complexes, [(phen)Pd(X)] + (X = F and Cl), readily react with vinyltrimethylsilane, Me 3 Si(CHCH 2 ), via transmetalation to give [(phen)Pd(CHCH 2 )] + as the major product. DFT calculations reveal that this transmetalation reaction is concerted and proceeds via a four-centered transition state, illustrating the role of coordinated halide in this gasphase system. Two minor side products are observed corresponding to transmetalation to give [(phen)Pd(CH 3 )] + and [(phen)Pd(SiMe 2 X)] + . DFT calculations suggest that these arise from the same initial Si to Pd methyl transmetalation pathway to give the [(phen)Pd(CH 3 ) + Me 2 (CH CH 2 )SiX] + intermediate, which either then loses Me 2 (CHCH 2 )SiX or reacts via C−C bond coupling to ultimately yield propene and [(phen)Pd(SiMe 2 X)] + . [(phen)Pd(CHCH 2 )] + undergoes a reaction with a second molecule of vinyltrimethylsilane to form an adduct, which upon collision-induced dissociation liberates 1,3-butadiene to form [(phen)Pd(SiMe 3 )] + . DFT calculations suggest a mechanism in which C−C bond formation is followed by migration of SiMe 3 from C to Pd. Links between the observed gas-phase chemistry and solution-phase Pd-mediated homocoupling reactions of vinyltrimethylsilanes are explored.

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Section: Introductionmentioning

confidence: 99%

Dissecting Transmetalation Reactions at the Molecular Level: Role of the Coordinated Anion in Gas-Phase Models for the Transmetalation Step of the Hiyama Cross-Coupling Reaction

et al. 2021

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“…Weakly coordinating anions such as the tetraphenylborate anion, [BPh 4 ] − , are widely used as counterions in inorganic and organometallic chemistry, with important applications in synthesis and industrial chemistry. − The oligomeric metal complexes of tetraphenylborate and related anions have recently been used as calibrants for traveling-wave ion mobility spectrometry experiments As part of an ongoing series of studies on the gas-phase chemistry of metal complexes of organoborates, − we were surprised to discover that, in the absence of CID, the ESI-MS/MS spectrum of the magnesium complex [Mg(BPh 4 )] + contains product ions resulting from IMRs with background water via two sequential protonolysis reactions of its B–C bonds. Here we used time-resolved MS/MS experiments and DFT calculations to explore these unusual reactions.…”

Section: Introductionmentioning

confidence: 99%

The Magnesium Dication and Water Synergistically Promote the Protonolysis of Two of the B–C Bonds in the Tetraphenylborate Anion

Aldajani,

Ma,

Yang

et al. 2024

J. Am. Soc. Mass Spectrom.

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Analytes are sampled from both solution phase and gas-phase environments during the ESI process, and thus, the mass spectrum that is measured can reflect both solution and gas-phase conditions. In the gas-phase regime, ion−molecule reactions can influence the types of ions that are observed. Herein, the synergistic effects of a Lewis acid (Mg 2+ ) and background water are shown to lead to protonolysis of two of the B−C bonds of the tetraphenylborate ion in the gas phase, giving rise to different ions at different reaction times in ESI-MS/MS experiments in a linear ion trap mass spectrometer. At short reaction times (1 ms), the expected adduct [Mg(BPh 4 )] + is observed. At 10 ms, [(HO)Mg(BPh 3 )] + and [(HO) 2 Mg(BPh 2 )] + are observed. At 100 ms, the water adducts [(HO) 2 Mg(BPh 2 )(H 2 O)] + and [(HO) 2 Mg(BPh 2 )(H 2 O) 2 ] + appear, and these become the dominant ions at longer reaction times. DFT calculations provide a plausible explanation as to why only [(HO)Mg(BPh 3 )] + and [(HO) 2 Mg(BPh 2 )] + but not [(HO) 3 Mg(BPh)] + are observed.

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Henkel‐like Decarboxylation Produces Mononuclear Arylalkalis, [4‐(CH₃)₃N(C₆H₄)M]⁺ which Hydrolyse and Undergo Surprising S_N2 Reactions Between Alkali Hydroxides and (CH₃)₃NC₆H₅⁺

Altalhi,

Canty,

O'Hair

2024

Eur J Inorg Chem

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Benzoate substituted with a cationic quaternary ammonium group at the para‐position, [4‐(CH3)3N(C6H4)CO2], forms mononuclear alkali metal ion complexes, [4‐(CH3)3N(C6H4)CO2M]+ (M=Li, Na, K, Rb and Cs), which are observed by electrospray‐ionisation mass spectrometry. When mass selected and subjected to collision‐induced dissociation each of these complexes undergoes decarboxylation to produce the mononuclear arylalkali complex cations, [4‐(CH3)3N(C6H4)M]+, which subsequently react with water via hydrolysis to yield the quaternary ammonium cation, (CH3)3NC6H5+. The unexpected product ions, [M((CH3)2NC6H5)]+, [M(CH3OH)]+, and M+, which are associated with the hydrolysis pathway, suggest an unusual reaction occurring within the exit channel ion‐molecule complex, [(CH3)3NC6H5+MOH]+. DFT calculations were used to examine the: decarboxylation reaction of [4‐(CH3)3N(C6H4)CO2M]+, which readily proceeds via a four‐centred transition state; the hydrolysis and SN2 reactions accounting for formation of products in the exit channel, which are connected via a roaming mechanism in which the metal hydroxide moiety migrates from the para‐hydrogen of (CH3)3NC6H5+ to one of the methyl groups.

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Dissecting transmetalation reactions at the molecular level: C–B versus F–B bond activation in phenyltrifluoroborate silver complexes

Abstract: Gas-phase experiments and computation provide fundamental model reactions for aryl and fluoride transfer between silver and boron centres.

Cited by 7 publications

References 66 publications

Dissecting Transmetalation Reactions at the Molecular Level: Role of the Coordinated Anion in Gas-Phase Models for the Transmetalation Step of the Hiyama Cross-Coupling Reaction

Dissecting Transmetalation Reactions at the Molecular Level: Role of the Coordinated Anion in Gas-Phase Models for the Transmetalation Step of the Hiyama Cross-Coupling Reaction

The Magnesium Dication and Water Synergistically Promote the Protonolysis of Two of the B–C Bonds in the Tetraphenylborate Anion

Henkel‐like Decarboxylation Produces Mononuclear Arylalkalis, [4‐(CH₃)₃N(C₆H₄)M]⁺ which Hydrolyse and Undergo Surprising S_N2 Reactions Between Alkali Hydroxides and (CH₃)₃NC₆H₅⁺

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Dissecting transmetalation reactions at the molecular level: C–B versus F–B bond activation in phenyltrifluoroborate silver complexes

Abstract: Gas-phase experiments and computation provide fundamental model reactions for aryl and fluoride transfer between silver and boron centres.

Cited by 7 publications

References 66 publications

Dissecting Transmetalation Reactions at the Molecular Level: Role of the Coordinated Anion in Gas-Phase Models for the Transmetalation Step of the Hiyama Cross-Coupling Reaction

Dissecting Transmetalation Reactions at the Molecular Level: Role of the Coordinated Anion in Gas-Phase Models for the Transmetalation Step of the Hiyama Cross-Coupling Reaction

The Magnesium Dication and Water Synergistically Promote the Protonolysis of Two of the B–C Bonds in the Tetraphenylborate Anion

Henkel‐like Decarboxylation Produces Mononuclear Arylalkalis, [4‐(CH3)3N(C6H4)M]+ which Hydrolyse and Undergo Surprising SN2 Reactions Between Alkali Hydroxides and (CH3)3NC6H5+

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Henkel‐like Decarboxylation Produces Mononuclear Arylalkalis, [4‐(CH₃)₃N(C₆H₄)M]⁺ which Hydrolyse and Undergo Surprising S_N2 Reactions Between Alkali Hydroxides and (CH₃)₃NC₆H₅⁺