Investigation of Group Migration in the Fragmentation ofBis(trimethylsilyl) Ethers of Diols Separated by Rigid Groups

Byun, Jaeman; Gross, Michael L.; George, M. C.; Parees, David M.; Kamzelski, A.Z.; Swijter, Dennis F. H.; Willcox, Dale A.

doi:10.1002/(sici)1096-9888(199701)32:1<71::aid-jms452>3.0.co;2-9

Cited by 20 publications

(14 citation statements)

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“…1,4‐ Bis ‐(trimethylsilyloxydimethyl)‐benzene ( 14 , Scheme ) in which the TMSO groups are well separated would not be expected to produce m/z 147 ( w ), yet again this ion appears. The explanation appears to be that the −O‐Si + (CH 3 ) 2 group from the [M − 15] + ion ( ak ) is able to interact with, and migrate across the phenyl ring by interaction with the π‐electron system in the form of an ion‐neutral complex ( al , Scheme ) in a process termed resonance charge delocalization, to interact with the Si(CH 3 ) 3 group in the para‐position of the other ring and form m/z 147 (Byun et al, ). Alternative electron shifts produce the ion at m/z 119 ( an ).…”

Section: Trimethylsilyl Derivativesmentioning

confidence: 99%

“…Fragmentation of the [M – 15] + ion from the TMS derivative of 1,4‐ bis ‐(trimethylsilyloxy)dimethylbenzene ( 14 ) involving migration of the TMS group across the phenyl ring (Byun et al., ).…”

Section: Trimethylsilyl Derivativesmentioning

confidence: 99%

“…The first is as above with the −O‐Si + (CH 3 ) 2 group derived from the loss of a methyl radical from a TMS group migrating across the molecule in an ion‐neutral complex. However, if the [M − 15] + ion is formed by loss of one of the methyl groups bound to carbon ( as ), the trimethylsilyl cation migrates ( at ) and forms the ion at m/z 147 ( av ) via a cyclic complex ( au , Scheme ) (Byun et al, ). Ion av probably rearranges to the siliconium form ( w ) as discussed above.…”

Section: Trimethylsilyl Derivativesmentioning

confidence: 99%

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Mass Spectrometric Fragmentation of Trimethylsilyl and Related Alkylsilyl Derivatives

Harvey

Vouros

2019

Mass Spectrometry Reviews

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This review describes the mass spectral fragmentation of trimethylsilyl (TMS) and related alkylsilyl derivatives used for preparing samples for analysis, mainly by combined gas chromatography and mass spectrometry (GC/MS). The review is divided into three sections. The first section is concerned with the TMS derivatives themselves and describes fragmentation of derivatized alcohols, thiols, amines, ketones, carboxylic acids and bifunctional compounds such as hydroxy‐ and amino‐acids, halo acids and hydroxy ethers. More complex compounds such as glycerides, sphingolipids, carbohydrates, organic phosphates, phosphonates, steroids, vitamin D, cannabinoids, and prostaglandins are discussed next. The second section describes intermolecular reactions of siliconium ions such as the TMS cation and the third section discusses other alkylsilyl derivatives. Among these latter compounds are di‐ and trialkyl‐silyl derivatives, various substituted‐alkyldimethylsilyl derivatives such as the tert‐butyldimethylsilyl ethers, cyclic silyl derivatives, alkoxysilyl derivatives, and 3‐pyridylmethyldimethylsilyl esters used for double bond location in fatty acid spectra. © 2019 Wiley Periodicals, Inc. Mass Spec Rev 0000:1–107, 2019

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Section: Trimethylsilyl Derivativesmentioning

confidence: 99%

Section: Trimethylsilyl Derivativesmentioning

confidence: 99%

Section: Trimethylsilyl Derivativesmentioning

confidence: 99%

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Mass Spectrometric Fragmentation of Trimethylsilyl and Related Alkylsilyl Derivatives

Harvey

Vouros

2019

Mass Spectrometry Reviews

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“…In general, electron ionization (EI) mass spectra of trimethylsilyl ethers or esters exhibit a significant [M Ϫ 15] ϩ ion formed by loss of a methyl group bonded to silicon, which is very useful in determining the molecular mass. It is very important to note that EI mass spectra of trimethylsilyl derivatives may be employed not only for molecular weight determinations, but also for structural deductions [4].Trimethylsilyl group migrations during EI fragmentation process are common [5,6] and take place by means of ion-neutral complexes [7]. These rearrangements are generally considered useful for deducing structures of unknown spectra [8]; however, in some cases, misleading conclusions may be drawn.…”

mentioning

confidence: 99%

“…Trimethylsilyl group migrations during EI fragmentation process are common [5,6] and take place by means of ion-neutral complexes [7]. These rearrangements are generally considered useful for deducing structures of unknown spectra [8]; however, in some cases, misleading conclusions may be drawn.…”

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confidence: 99%

Hydrogen and trimethylsilyl transfers during EI mass spectral fragmentation of hydroxycarboxylic and oxocarboxylic acid trimethylsilyl derivatives

Rontani

Aubert²

2008

J. Am. Soc. Mass Spectrom.

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This paper, describing electron ionization mass spectral fragmentation of some hydroxycarboxylic and oxocarboxylic acid trimethylsilyl derivatives, focuses on the formation of fragment ions resulting from the interactions between the two functionalities of these compounds. These interactions result in the formation of fragment ions at [CH 2 ilylation is by far the major derivatization procedure for GC/MS analyses [1][2][3]. Silyl derivatives are formed when active proton displacement (in ϪOH, ϪSH, or ϪNH groups) by an alkylsilyl group occurs. The most common silylation procedure is trimethylsilylation. Trimethylsilyl derivatives combine thermal stability and high volatility. In general, electron ionization (EI) mass spectra of trimethylsilyl ethers or esters exhibit a significant [M Ϫ 15] ϩ ion formed by loss of a methyl group bonded to silicon, which is very useful in determining the molecular mass. It is very important to note that EI mass spectra of trimethylsilyl derivatives may be employed not only for molecular weight determinations, but also for structural deductions [4].Trimethylsilyl group migrations during EI fragmentation process are common [5,6] and take place by means of ion-neutral complexes [7]. These rearrangements are generally considered useful for deducing structures of unknown spectra [8]; however, in some cases, misleading conclusions may be drawn. Though trimethylsilyl group migrations usually occur through five-to eight-member-ring transition states [9], intense long-range migration of the trimethylsilyl group was previously observed in the case of trimethylsilyl derivatives of some steroid compounds [8, 10 -13]. The capability of the trimethylsilyl group to migrate over a wide range of distances was also demonstrated in the case of semirigid or rigid molecules [5]. Recently, a significant transfer of trimethylsilyl group towards the carbonyl group was also observed during EI fragmentation of the trimethylsilyl derivatives of long-chain -hydroxycarboxylic and -dicarboxylic acids [14], showing that such migrations may also occur in the case of nonrigid structures.Hydrogen transfers between distant functionalities during EI fragmentation processes are also well known [6,15,16], for this reaction hydrogen activation is needed and is caused by groups such as keto, amino, ether, trimethylsilyloxy, as well as by chain branching and unsaturation.In the present work, which is a part of a more general study of the synergistic effects during EI mass fragmentation of polyfunctional compounds [14,[17][18][19], we describe EI mass spectral fragmentation of several hydroxycarboxylic and oxocarboxylic acid trimethylsilyl derivatives, which involves trimethylsilyl and hydrogen transfers.The characterization of such compounds appears to be of great environmental importance [20,21]. Indeed, it was previously demonstrated that autoxidative processes could induce a bias during alkenone-based paAddress reprint requests to Dr.

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Reactions of silyl cations with ketones in the gas phase

1999

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Investigation of Group Migration in the Fragmentation ofBis(trimethylsilyl) Ethers of Diols Separated by Rigid Groups

Cited by 20 publications

References 8 publications

Mass Spectrometric Fragmentation of Trimethylsilyl and Related Alkylsilyl Derivatives

Mass Spectrometric Fragmentation of Trimethylsilyl and Related Alkylsilyl Derivatives

Hydrogen and trimethylsilyl transfers during EI mass spectral fragmentation of hydroxycarboxylic and oxocarboxylic acid trimethylsilyl derivatives

Reactions of silyl cations with ketones in the gas phase

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