The vibrational spectrum and chemical constitution of trimethylsilylvinyl ether, (CH3)3SiOCHCH2

Лазарев, А. Н.; Ignat'ev, I. S.; Schukovskaya, L.L.; Pal'chik, R. I.

doi:10.1016/0584-8539(71)80131-9

Cited by 18 publications

(5 citation statements)

References 11 publications

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“…However in the later publication of these authors [18] the normal coordinate analysis carried out for several conformers of the discussed molecule led to the confirmation of the conclusion of Lazarev et al [16], made by the analysis of experimental spectra, that the main isomer has the antiperiplanar structure.…”

Section: Introductionmentioning

confidence: 54%

“…Although in the work by Lazarev et al [16] the experimental vibrational spectra evidenced the fact that the main isomer was the antiperiplanar one, the analysis of the vibrational spectra leading to this conclusion was based on classical normal coordinate calculations and analogies with methyl vinyl ether. Here, for the first time, we calculated the spectra of two isomers from quantum chemical force constants.…”

Section: Trimethylsilyl Vinyl Ethermentioning

confidence: 96%

“…Moreover, due to the further increase of the oxygen charge upon C/Si substitution, hyperconjugative interactions, stabilizing the synperiplanar form grow up (Table 4). Nevertheless, the analysis of the vibrational spectrum of this molecule allowed Lazarev et al [16] to propose the antiperiplanar form to be the main isomer. Later this conclusion was confirmed from the electron diffraction study by Shen [15].…”

Section: Trimethylsilyl Vinyl Ethermentioning

confidence: 98%

“…The assignment of the observed bands for both conformers based on these predictions is also reported. Previous arguments in favor of the structure with the Si-O-C@C torsional angle close to 180°for the main conformer were based on the inverse order of frequencies for the first and second isomers in methyl and Table 5 The observed vibrational spectra of trimethylsilyl vinyl ether and theoretical (B3LYP) vibrational frequencies (cm À1 ) of the main isomer with the vinyl group modes of the second isomer trimethylsilyl ethers [16]. For example, in methyl vinyl ether among the pairs of bands corresponding to different rotamers the low-frequency component of mC@C, dCH 2 , qCH 2 , and wCH 2 should be assigned to the main isomer, while for dCH, wCH, m s COC, and dCCO the high-frequency components belong to this isomer.…”

Section: Trimethylsilyl Vinyl Ethermentioning

confidence: 99%

“…trimethylsilyl vinyl ether [15]. Earlier Lazarev et al [16] have found the existence of two isomers in their study of IR and Raman spectra of the liquid phase of this compound and ascribed the main isomer to the antiperiplanar form. Déd-ier et al [17] recorded the IR and Raman spectra in liquid and solid phases of the parent molecule and its deuterated derivatives (CD 3 ) 3 SiOC 2 H 3 and (CH 3 ) 3 SiOC 2 D 3 and, by the analysis of these spectra, proposed the main conformer to be an anticlinal one (without indications of the / value) and the synperiplanar isomer as the second.…”

Section: Introductionmentioning

confidence: 97%

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Structure and vibrational spectra of vinyl ether conformers. The comparison of B3LYP and MP2 predictions

et al. 2007

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Section: Introductionmentioning

confidence: 54%

Section: Trimethylsilyl Vinyl Ethermentioning

confidence: 96%

Section: Trimethylsilyl Vinyl Ethermentioning

confidence: 98%

Section: Trimethylsilyl Vinyl Ethermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

See 3 more Smart Citations

Structure and vibrational spectra of vinyl ether conformers. The comparison of B3LYP and MP2 predictions

et al. 2007

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1,3‐Dithienium‐ und 1,3‐Dithioleniumsalze, V. Bestimmung der relativen Reaktivität von 1,3‐Dithian‐2‐ylium‐tetrafluoroboraten durch intermolekularen Hydrid‐Ionen‐Transfer

Stahl

1985

Chem. Ber.

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Die 1,3-Dithienium-bzw. 1,3-Dithiolenium-tetrafluoroborate 4 (n = 3,2) reagieren in guten Ausbeuten mit den aus 0-Dicarbonylverbindungen erhaltlichen (Trimethylsi1oxy)alkenen 3 zu den 2-substituierten 1,3-Dicarbonylverbindungen 5. lnfolge der Bildung der Difluoroborsaureester 8 als Konkurrenzprodukte mu0 3 allerdings im UberschuD eingesetzt werden. Umsetzung von 4 (n = 3) mit 1,3,5-Cycloheptatrien (10) fuhrt zu den 1,3-Dithianen 11 und dem stabileren Tropylium-tetrafluoroborat (12). Die Bestimmung der entsprechenden Reduktionsgeschwindigkeiten gestattet in einfacher Weise die Ermittlung der relativen Reaktivitaten von 4. Wahrend die Reaktivitaten der arylsubstituierten Vertreter von 4 eine befriedigende Korrelation entsprechend der Hammett-Beziehung zeigen, kann die Reaktivitatsabstufung der alkylsubstituierten Salze 4 auf der Basis hyperkonjugativer Stabilisierung erklart werden. The 1,3-dithienium-and 1,3-dithiolenium tetrafluoroborates 4 (n = 3,2) react in good yields with the (trimethylsi1oxy)alkenes 3 available from P-dicarbonyl compounds to give the 2-substituted 1,3-dicarbonyl compounds 5. Owing to the formation of the difluoroboron acid esters 8 as competition products 3 has to be employed in excess, however. Reaction of 4 (n = 3) with 1,3,5-cycloheptatriene (10) leads to the 1,3-dithianes 11 and the more stable tropylium tetrafluoroborate (12). The determination of the corresponding rates of reduction allows in a simple manner the ascertainment of the relative reactivities of 4. Whereas the reactivities of the aryl-substituted representatives of 4 show a sufficient correlation corresponding to the Hammett relationship, the variations of the reactivities of the alkyl substituted salts 4 can be explained on the basis of hyperconjugative stabilization.Silylenolether stellen auI3erordentlich wichtige Reagenzien fur Synthesen da?.3). Sie verfugen infolge der sich vom 0 -A t o m leicht wieder abspaltenden Trialkylsilylreste uber wertvolle Schutzgruppeneigenschaften zur Stabilisierung labiler Hydroxyverbindungen. IR-und Raman-spektroskopische Unters~chungen~) haben

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On the mechanism of diels‐alder reactions of nitroso alkenes: exo/endo selectivity, stereospecificity, E/Z selectivity, and relative reactivity of various olefins

1990

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The mechanism of the hetero Diels-Alder reaction of nitroso alkenes 2 with silyl enol ethers and other olefins has been investigated. Using the bicyclic nitroso compound 2a a study of the exolendo selectivity has demonstrated that the ex0 approach is preferred with the siloxyethene l a as dienophile. On the other hand, the siloxycyclopentene 1 c gives a mixture of cycloadducts 3c with an excess of endo product (endo: exo 82: 18). The stereospecificity of the nitroso alkene cycloaddition could be demonstrated with the stereochemically homogeneous silyl enol ethers 1 b and 1 d. Experiments with enol ethers 1 f and 1 g also occur stereospecifically. a-Nitrososty-rene 2b reveals surprisingly high kEIz values when EIZ-isomeric olefins are compared in competition experiments. Also, a detailed reactivity scale of 2b including various structurally different silyl enol ethers and other typical dienophiles shows that a complex interplay of electronic and steric effects is operating. The large influence of steric effects is taken as evidence for a highly ordered transition state in the cycloaddition. All mechanistic details for the Diels-Alder reactions of nitroso alkenes 2 with (silyl) enol ethers are in strong accord with a concerted mechanism and exclude the involvement of zwitterions or diradicals as intermediates.In a previous account3' we have reported on the regioselective synthesis of 6-siloxy-substituted 5,6-dihydro-4H-1,2-0xazines (abbreviated as 1,2-oxazines) from silyl enol ethers 1 and nitroso alkenes 2. According to Gilchrist4), reactive intermediates 2 are easily generated in situ by base treatment of the corresponding a-halogen oximes. R G R RSSiO 2Characteristic features of this cycloaddition are high yields and a broad variability with respect to component 1. For this reason it can serve as an ideal model reaction for the study of all relevant mechanistic details of a Diels-Alder reaction with inverse electron demand5). Although several aspects have been investigated by Gilchrist and coworkers6), not all of their results are conclusive (e.g. stereospecificity of the cycloaddition). For the anticipated synthetic use') of 1,2oxazines, however, full understanding of the mechanism is an indispensable prerequisite. In this paper we will deal with the stereospecificity, the exolendo and EIZ selectivity of nitroso alkenes as well as with the relative reactivity of silyl enol ethers 1, or other suitable olefins, towards 2. exolendo Selectivity of 3,CDihydro-1 -nitrosonaphthaleneIn an intramolecular nitroso alkene cycloaddition an endo-selective reaction has been reported (exo: endo = 1 : 3.4)8). To study this stereochemical feature in the geometrically less restricted intermolecular reaction we have employed 3,bdihydro-1 -nitrosonaphthalene (2a). This compound incorporates an E-nitroso alkene moiety and is generated from the bromo oxime 4a, which can easily be prepared from a-tetralone. 3a l a R = H l b CH3 Na2C03 2al \ (exo/endo > 97:3) 4a 3 b (exo/endo -64:36)Cycloaddition of 2a to trimethylsiloxy ethene (1 a) a...

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The vibrational spectrum and chemical constitution of trimethylsilylvinyl ether, (CH3)3SiOCHCH2

Cited by 18 publications

References 11 publications

Structure and vibrational spectra of vinyl ether conformers. The comparison of B3LYP and MP2 predictions

Structure and vibrational spectra of vinyl ether conformers. The comparison of B3LYP and MP2 predictions

1,3‐Dithienium‐ und 1,3‐Dithioleniumsalze, V. Bestimmung der relativen Reaktivität von 1,3‐Dithian‐2‐ylium‐tetrafluoroboraten durch intermolekularen Hydrid‐Ionen‐Transfer

On the mechanism of diels‐alder reactions of nitroso alkenes: exo/endo selectivity, stereospecificity, E/Z selectivity, and relative reactivity of various olefins

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