Formation of endo acetate in acetolysis of a fused endo-norbornyl brosylate via C-7 participation

Howe, Robert K.; Winstein, S.

doi:10.1021/jo00956a013

Cited by 6 publications

(1 citation statement)

References 4 publications

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“…Remarkably, the tetrahydrofuran and triazolinedione rings are tilted toward each other; the oxadiazolidine ring adopts an envel-ope conformation with the oxygen lying 0.58 (0.64) Å above the C11-C12-N14-N15 plane. Homoconjugate Additions [6,7a,44] In syn-periplanar dienes of type A' the syn-periplanar π,π-alignment is set up for homoconjugate additions, [45] not amenable, however, to [2ϩ2ϩ2]cycloadditions as e.g. routinely observed with tilted homodienes such as norbornadiene.…”

Section: Full Papermentioning

confidence: 99%

Proximate,syn-Periplanar, Rigid Imine(Nitrone)/Ene-, and Diazene(Diazeneoxy)/Ene Systems: Syntheses, Homoconjugate Reactivity and Photochemistry

Fischer¹,

Fritz

Rihs

et al. 2000

Eur. J. Org. Chem.

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The chances for intramolecular imine/ene (→ azetidines), diazene/ene (→ 1,2‐diazetidines), diazeneoxy/ene (→ 1,2‐diazetidine oxides) and diazenedioxiene (→ 1,2‐diazetidine dioxides) [2+2]photocycloadditions and for the isolation of the respective photoproducts, have been probed with specifically designed substrates. Upon direct or sensitized excitation, [2+2]cycloaddition was found to be the exclusive or at least dominant chemical process for the CN/CC, NN/CC and ONN(O)/CC systems featuring very small π,π‐distances of 2.8‐3.0 Å and large π,π‐interorbital angles of 160‐170° (7 → 51, 17 → 55, 33 → 58 (competing N2 elimination), 22 → 62). This is not the case, however, in ONNO/CC (23, where electron transfer is a possibility), or in the more flexible, less “proximate” CN/CN (57) and CNO/CN (63) systems (π,π‐distances of >3.8 Å). While the corseted 1,2‐diazetidine photoadducts (55, 58) proved to be thermally stable, their N‐oxides (62, 65) were thermally too labile to be directly observable above ‐65 °C. For the latter's only fleeting existence, electronic rather than strain effects are held responsible (B3LYP/6‐31G* calculations). Very facile CNO/CC (12 → 13) and NNO/CC (22 → 24) [3+2]cycloadditions, homoconjugate addition of H2 and of dienophiles ([2+2+2]) to the diazene/ene 17 (→ 39, 41, 45) are manifestations of “proximity” in these bichromophoric skeletons.

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Section: Full Papermentioning

confidence: 99%

Proximate,syn-Periplanar, Rigid Imine(Nitrone)/Ene-, and Diazene(Diazeneoxy)/Ene Systems: Syntheses, Homoconjugate Reactivity and Photochemistry

Fischer¹,

Fritz

Rihs

et al. 2000

Eur. J. Org. Chem.

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ChemInform Abstract: FORMATION OF ENDO ACETATE IN ACETOLYSIS OF A FUSED ENDO‐NORBORNYL BROSYLATE VIA C‐7 PARTICIPATION

Howe¹,

Winstein²

1973

Chemischer Informationsdienst

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Azo Bridges from Azines, XX.

Brand

Hünig

1996

Liebigs Ann./Recl.

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Reaction of 4 with our "workhorse" 1) NaOH 2) nco, Liebigs Ann. 1996,585-592 0 VCH Verlagsgesellschaft mbH, D-69451 Weinheim, 1996 0947 -3440/96/0404 ~ 0585 $ 1 5 .OO + .25/0 5 8 5 U. Brand, S. Hiinig FULL PAPERane and trimethylsilyl chloride which on addition of triethylamine form the corresponding silyl nitronate. Although [3 + 21 cycloaddition of the latter to styrene (41%) is hampered by self-condensation of the nitronate[*I, quantitative formation of l l a , b from 10 is achieved, if the 1,3dipole is produced slowly within 3 days in a 2.5-fold excess (here and in forthcoming formulae a, b denominates the two isomers with respect to the double bond in the cyclopentene moiety). Heating of 11 a, b in triethylamine affords the hydroxy nitrile 12a, b in high yield. Both l l a , b and 12a, b are smoothly hydrogenated to their saturated counterparts llsat (in CH,Cl,) and 12sat (in MeOH), respectively (here and in the following "sat" means that these products differ from their starting material only by the saturated cyclopentane ring). For l l a , b in methanol as the solvent a mixture of llsat and 12sat is obtained. Interestingly, llsat is so much less soluble in triethylamine (higher symmetry responsible?) that the transformation to 12sat proceeds only with a cosolvent in a reasonable time. 10 a,b NC b) . 93 % 79 % ! = I d)]91 % % 74 e) % . H a 11 sat 12 sat a) NEt, + Me,SiCI in C,H,, Me NO, added over 3d; b) NEt, (solvent) 2d reflux; c) PdlC, H, , CH, CI , , 3d; d)Pd/C, H,, MeOH, 36h; e) Et,N/C,H, 1 :1, 3d reflux.

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Formation of endo acetate in acetolysis of a fused endo-norbornyl brosylate via C-7 participation

Cited by 6 publications

References 4 publications

Proximate,syn-Periplanar, Rigid Imine(Nitrone)/Ene-, and Diazene(Diazeneoxy)/Ene Systems: Syntheses, Homoconjugate Reactivity and Photochemistry

Proximate,syn-Periplanar, Rigid Imine(Nitrone)/Ene-, and Diazene(Diazeneoxy)/Ene Systems: Syntheses, Homoconjugate Reactivity and Photochemistry

ChemInform Abstract: FORMATION OF ENDO ACETATE IN ACETOLYSIS OF A FUSED ENDO‐NORBORNYL BROSYLATE VIA C‐7 PARTICIPATION

Azo Bridges from Azines, XX.

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