Pyrolysis of Esters of Borneol and isoBorneol

Bunton, Clifford A.; Khaleeluddin, K.; Whittaker, D.

doi:10.1038/190715a0

Cited by 12 publications

(1 citation statement)

References 4 publications

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“…Kwart and Hoster [22], on the other hand support a "concerted transition state without indication of charge development therein" based on rearrangement products. Rearrangements are generally reported in systems without @-hydrogens [22], in bridged [28,29,311 or spiro systems [26]. Great care must be taken to determine the source of the products as the rearranged products may simply be a result of thermal rearrangement of the "normal" olefins.…”

Section: Discussion Of Resultsmentioning

confidence: 99%

Activating effects of unsaturated and cyclopropyl groups in gas phase pyrolysis of acetates. Paper XVIII

Lum

Smith

1969

Int J of Chemical Kinetics

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The activating effects of a number of unsaturated groups and a cyclopropyl group have been evaluated in a solvent free system by determining the absolute rate constants, and energies and entropies of activation in the vapor phase pyrolysis of secondary and tertiary esters of the type RC(R'CH,)OAc where R' = H or CH, and R = c-Pr, i-Pr, CH,, CH,=CH, CH,=CHCH,, C,H, ; the cyclopropyl showed only a moderate activating effect. The results are in contrast to the very significant activating effect of a cyclopropyl group in solvolysis of cyclopropylcarbinyl derivatives. iZpparently marked activation by this group occurs only when a highly developed positive center forms adjacent to it. The lack of marked activation by the cyclopropyl group supports a mechanism for ester pyrolysis which involves a modest, but detectable, charge separation in the transition state [Z] but questions a mechanism in which a n intimate ion-pair was proposed [3].

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Section: Discussion Of Resultsmentioning

confidence: 99%

Activating effects of unsaturated and cyclopropyl groups in gas phase pyrolysis of acetates. Paper XVIII

Lum

Smith

1969

Int J of Chemical Kinetics

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Structure‐Reactivity Relationships in Homogeneous Gas‐Phase Reactions: Thermolyses and Rearrangements

Smith¹,

Kelly²

1971

Progress in Physical Organic Chemistry

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Desaminierungsreaktionen, 14. Bornyl‐ und Fenchyldiazonium‐Ionen in alkalischen Medien

Kirmse

Arend

1972

Chem. Ber.

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Bornyl-und Fenchyldiazonium-Ionen wurden durch Belichtung von Campher-benzolsulfonylhydrazon (11) und Fenchon-p-toluolsulfonylhydrazon (17) in Natronlauge oder Methanol/Natriummethylat erzeugt. Unter diesen Bedingungen konnte die Umlagerung von der Bornan-in die Pinanreihe erstmals durch den Nachweis der Pinenhydrate 27 und 28 (R = H) und ihrer Methylather (R = CH3) gesichert werden. Die Produktverhaltnisse fordern das Auftreten stereoisomerer Pinyl-Kationen, die sich ineinander umlagern. Deamination Reactions, 14 ' ) Bornyl-and Fenchyldiazonium Ions in Alkaline MediaBornyl-and fenchyldiazonium ions have been generated by photolysis of camphor benzenesulfonylhydrazone (11) and fenchone p-toluenesulfonylhydrazone (17), respectively, in aqueous sodium hydroxide and in methanol/sodium methoxide. Under these conditions, rearrangement from the bornane to the pinane series has been demonstrated by the detection of pinene hydrates, 27 and 28 (R = H), and of their methyl ethers (R = CH3). The product ratios require the intervention of two stereoisomeric, interconvertible piny1 cations.rn Hiickel und Mitarbb.3) erhielten bei der Desaminierung von endo-Bornylamin (1) und endo-Fenchylamin (5) neben Bicyclo[2.2.1 Iheptan-Derivaten auch a-Terpineol (7), Limonen (8) und Terpinolen (9). Diese Produkte entstanden aus den entsprechenden exo-Aminen nicht. Hiickel deutet sie als Folge einer Umlagerung zum PinylKation (3), ,,dessen Vierring in statu nascendi unter Energiegewinn geoffnet ~ird'~3.4). Wahrend das Bornyldiazonium-Ion 2 eine Spaltung zwischen C-1 und C-7 eingehen kann, die zu 6 fiihrt, verlauft der einzig plausible Weg von 4 nach 6 uber 3. Bisher ist es nicht gelungen, die Umwandlung 2 --f 3 oder 4 + 3 direkt nachzuweisen5). Wir berichten in dieser Arbeit iiber das Abfangen von 3 bei Desaminierungen in alkalischer Losung. (1968). 5) Eine Wagner-Meerwein-Umlagerung unter 1.2-Verschiebung von C-7 wurde bei der saurekatalysierten Zersetzung des 3-Diazo-norcampherssa) und bei der Desaminierung von 2-endo-Arnino-3-exo-phenyl-norbornano1-(3) 5b) beobachtet. 5a) P . Yates und R . J .CrawJord, J. Amer. chern. SOC. 88, 1561SOC. 88, (1966; 5b) C. J. Collins, V. F. Raaen, B. M .Benjamin und I. T. Glover, ebenda 89, 3940 (1967).

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Pyrolysis of Esters of Borneol and isoBorneol

Cited by 12 publications

References 4 publications

Activating effects of unsaturated and cyclopropyl groups in gas phase pyrolysis of acetates. Paper XVIII

Activating effects of unsaturated and cyclopropyl groups in gas phase pyrolysis of acetates. Paper XVIII

Structure‐Reactivity Relationships in Homogeneous Gas‐Phase Reactions: Thermolyses and Rearrangements

Desaminierungsreaktionen, 14. Bornyl‐ und Fenchyldiazonium‐Ionen in alkalischen Medien

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