Bicyclanes—I

Kooyman, E. C.; Vegter, G.C.

doi:10.1016/0040-4020(58)80059-9

Cited by 48 publications

(17 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The mixture contained unchanged ( 16) and (Me,Si),NH together with four main products. Peak 1: the mass spectrum showed this to be a monobromide C7H1 lBr; the ' and 'H n.m.r.. spectra were identical with those given in the literature3' for l-bromonorbornane (18). Peak 2 was shown to be bromobenzene.…”

Section: Methodssupporting

confidence: 70%

Free radical reactions of bicyclo[2.1.1]hexane and bicyclo[2.2.1]heptane

Walton¹

1988

J. Chem. Soc., Perkin Trans. 2

View full text Add to dashboard Cite

t-Butoxyl radicals abstract hydrogen from C(2) of bicyclo[2.1 .l] hexane (3) to give bicyclo[2.1 .I] hexan-2-yl radicals (6). At T > 250 K radicals ( 6 ) rearrange b y p-scission t o cyclopent-3enylmethyl radicals; both species were observed b y e.p.r. spectroscopy. In spite of the much greater ring strain the activation energy for rearrangement of (6) is about the same as that of cyclobutylmethyl radicals. Bromine atoms abstract hydrogen from C(2) of (3), but bis(trimethylsilyl)aminyl radicals abstract the bridgehead methine hydrogen at C ( l ) as well as the methylene hydrogens at C(2). There is very little abstraction of the bridgehead hydrogen in bicyclo[2.2.1] heptane b y bis(trimethylsilyl)aminyl radicals. Thus, the greater bridgehead reactivity of (3) as compared with the bridge positions is not simply due to the lower selectivity of the bis(trimethylsilyl)aminyl radicals, but is an intrinsic property of the bicycloalkane.

show abstract

Section: Methodssupporting

confidence: 70%

Free radical reactions of bicyclo[2.1.1]hexane and bicyclo[2.2.1]heptane

Walton¹

1988

J. Chem. Soc., Perkin Trans. 2

View full text Add to dashboard Cite

show abstract

“…In these reactions, the increase of stereospecificity was previously attributed to the relatively lower accessibility of the intermediate 2-norbornyl radical with bulkier reagents on the endo side. 8 The absence of a reaction in the dark, as well as the inhibition observed during photostimulation in presence of p-DNB, suggests that these reactions occur by an S RN 1 mechanism (Scheme 1). When 2-BrNor receives one electron, it is fragmented at the C-Br bond by a dissociative electron transfer (DET) process.…”

Section: Resultsmentioning

confidence: 99%

“…Isolation and identification of the products 2-Norbornyldiphenylphosphine oxide (1). exo-GC-MS (EI + ) m/z (%): 296 (24), 295 (61), 230 (15) (8), 96 (9), 95 (100), 79 (14), 67 (34), 65 (11). endo-GC-MS (EI + ) m/z (%): 206 (1), 205 (3), 204 (M + ) (20), 110 (20), 109 (6), 96 (7), 95 (100), 79 (6), 67 (29), 65 (9).…”

Section: General Proceduresmentioning

confidence: 99%

Reactions of halonorbornane and oxo-substituted derivatives with different anions by the electron transfer mechanism; redox catalysis in stabilized radicals

Uranga

Santiago

2010

New J. Chem.

View full text Add to dashboard Cite

Reactions of 2-bromo-, 2-chloronorbornane, 3-chloronorbornan-2-one and 3-bromocamphor with Me 3 Sn À , Ph 2 P À or PhS À ions were studied by an S RN 1 mechanism in liquid ammonia or DMSO. The results show that substrates having a carbonyl group facilitate electron transfer reactions, which are impeded in the absence of such a group. However, when the free radical formed is stabilized by conjugation, the coupling reaction decreases, causing a concomitant increase in the reduction product. Theoretical studies explain the observed reactivity on the basis of a mechanism involving reductive cleavage as a function of the p-s interactions.

show abstract

“…-au cours de la premiere &ape de la phase de propagation de la reaction, les radicaux t-butoxyle arrachent des atomes d'hydroghe en a (position 3) ou en 6 (position 6 ) du carbonyle des molecules de substrat ; comme les radicaux t-butoxyle sont plut8t Blectroaccepteurs, il n'est pas exclu que l'arrachement se fasse un peu mieux sur le sommet 6 moins affect6 par l'effet electroattracteur du carbonyle. Cette moindre nucleophilie du radical en 6 , correspondant une densite dlectronique abaissee, pourrait &re due B une interaction Blectronique avec le carbonyle, interaction rendue possible comme le montre le schema ci-dessous, par la structure particuliere de la molecule de norhornanone-2 ; une telle hypothese a du reste Bt6 deji formulde dans le cas du m6thylPne-2 norbornane ( 12,14) . : I1 a 6td prepare suivant un mode opera-…”

Section: Identification Des Derives Acetonyles Isomeresunclassified

Acétonylation Radicalaire de la Norbornanone‐2 Par Réaction Avec le Percarbonate de O,O‐t‐Butyle et O‐Isopropenyle

Villenave

Jaouhari

Baratchart

et al. 1983

Bulletin des Soc Chimique

View full text Add to dashboard Cite

Ahstract -The free radical decomposition of 0,O-t-butyl and 0-isopropenyl peroxycarbonate in 2-norbornanone leads to isomeric derivatives of the solvent. The products are identified using 13c MdR spectroscopy. The composition of the reaction mixture depends on the concentration of the peroxycarbonate solutions. At lowest concentrations, intermolecular transfer reactions enhance markedly the relative amounts of the 3-acetonylated isomer. -addition de ce radical S ' sur la double liaison du percarbonate provoquant la decomposition de ce dernier avec formation de derives acetonylds 2 et de gaz carbonique ainsi que la regeneration du radical t-butoxyle.Apres notre etude generale, nous avons envisage de maniere plus detaillee le comportement du percarbonate 1 dans divers milieux ( 2 -4 ) . Dans le cas des cyclanones ( 4 ) , nous nous sommes trouvds confrontes ?i un problsme particulier, les proportions relatives des deriv6s isomeres obtenus ne correspondant pas i la reactivite, vis ?i vis des radicaux t-butoxyle, des differents atomes de carbone de la molecule de substrat. Aux faibles concentrations en percarbonate notamment, la reaction conduisait selectivement au derive a-acetony16 en raison de l'existence de reactions de transfert intermoleculaires de radicaux en B ou y du carbonyle vers les positions en a de celui-ci.I1 nous a paru alors interessant de soumettre la norbornanone-2 3 i l'action du -1 6 7 -

show abstract

Bicyclanes—I

Cited by 48 publications

References 15 publications

Free radical reactions of bicyclo[2.1.1]hexane and bicyclo[2.2.1]heptane

Free radical reactions of bicyclo[2.1.1]hexane and bicyclo[2.2.1]heptane

Reactions of halonorbornane and oxo-substituted derivatives with different anions by the electron transfer mechanism; redox catalysis in stabilized radicals

Acétonylation Radicalaire de la Norbornanone‐2 Par Réaction Avec le Percarbonate de O,O‐t‐Butyle et O‐Isopropenyle

Contact Info

Product

Resources

About