The Collision-Induced Dissociations of Deprotonated Isopropyl and t-Butyl Ketones. Some Unusual Alkyl Migrations

Alexander, M. J.; Bowie, J. H.; Hayes, RN

doi:10.1071/ch9902027

Cited by 3 publications

(13 citation statements)

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“…Although we do not observe H 2 loss in the infrared multiple photon dissociation of 3,3-dimethyl-2-butanone enolate ions, Bowie observes H 2 loss in the collisional activation of 3,3-dimethyl-2-butanone enolate ions . The H 2 loss can be explained by a 1,3-methyl rearrangement.…”

Section: Discussioncontrasting

confidence: 73%

“…Background. The unimolecular fragmentation reactions of simple alkyl enolate ions have been studied by both collisional activation and infrared multiple photon activation techniques in mass spectrometers. − ,− The major fragmentation reactions are well understood and explained by generalized pathways . These pathways fall into two classes.…”

Section: Discussionmentioning

confidence: 99%

“…Bowie and co-workers observed unusual fragmentations in the collisional activation of 3-methyl-2-butanone and 3,3-dimethyl-2-butanone enolate ions that do not follow the above generalized pathways . In order to explain the unusual fragmentations, Bowie and co-workers proposed the homoenolate ion as a key intermediate.…”

Section: Discussionmentioning

confidence: 99%

“…Several groups have studied the collisional activation of simple alkyl enolate ions. − Some generalized pathways were developed to explain the observed unimolecular fragmentations…”

Section: Introductionmentioning

confidence: 99%

“…Bowie and co-workers studied the collisional activation of 3-methyl-2-butanone and 3,3-dimethyl-2-butanone enolate ions …”

Section: Introductionmentioning

confidence: 99%

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Rearrangement and Fragmentation Mechanisms of Vibrationally Activated Enolate Ions in the Gas Phase

and¹,

Brauman²

1996

J. Phys. Chem.

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The unimolecular rearrangement and fragmentation mechanisms of several alkyl enolate ions have been investigated using Fourier transform ion cyclotron resonance mass spectrometry and infrared multiple photon activation techniques. We have observed unusual fragmentations induced by infrared multiple activation of several enolate ions that do not follow previously generalized pathways. Two new mechanisms are proposed to explain the unusual fragmentations. First, we propose the intermediacy of an alkyl radical/ketene radical anion complex that is formed by homolytic cleavage. This complex is expected when the alkyl anion is unbound. Within this complex, the alkyl radical can either abstract a hydrogen from the ketene radical anion to form deprotonated ketene anion and an alkane or transfer a hydrogen to the ketene radical anion to form an aldehyde enolate ion and an alkene. Second, we propose that vibrationally activated enolate ions can undergo a 1,3-methyl rearrangement in addition to a 1,3-hydrogen rearrangement. The proposed mechanisms appear to be general and are able to predict the fragmentations of other enolate ions.

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Section: Discussioncontrasting

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

“…Several groups have studied the collisional activation of simple alkyl enolate ions. − Some generalized pathways were developed to explain the observed unimolecular fragmentations…”

Section: Introductionmentioning

confidence: 99%

“…Bowie and co-workers studied the collisional activation of 3-methyl-2-butanone and 3,3-dimethyl-2-butanone enolate ions …”

Section: Introductionmentioning

confidence: 99%

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