Electrochemical oxidation of [1.1.1.1]pagodanes, bisseco-, seco- and dodecahedra(di)enes: stability of caged 4c/3e radical cations and 4c/2e dications

Weber, Klaus; Lütz, Georg; Knothe, Lothar; Mortensen, John; Heınze, Jürgen; Prinzbach, Horst

doi:10.1039/p29950001991

Cited by 20 publications

(24 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In a prior report on the electrochemical experiments with homoconjugated dienes (inter alia 1a,b, 2b, and 3a) a first oxidation potential of ca. 0.8 V had been estimated for 2a [8]. The experimental value was now found to be pretty close (Fig.…”

Section: Scheme 10mentioning

confidence: 52%

“…IR (KBr): 1782 (CO, partial hydrolysis). (20) .0 6,10 .0 8,12 .0 11,15 .0 13,17 .0 16,20 ]icosane (24a).To a homogeneous soln. of diacyl dichloride (145 mg, 0.40 mmol) in CBrCl 3 (30 ml), 2-mercaptopyridine 1-oxide Na salt (160 mg, 1.10 mmol) and DMAP (N,N-dimethylpyridin-4-amine; 6 mg) were added and stirred under reflux till the yellowish soln.…”

Section: Scheme 16mentioning

confidence: 99%

“…(18)). (3')); 128.9 (C(2'), C(4')); 128.5 (C(5'), C(6')); 126.9 (C(1')); 116.5 (C (20) (2'), HÀC(2''), HÀC(4'), HÀC(4'')); 7.36 (m, HÀC(5'), HÀC(5''), HÀC(6'), HÀC(6'')); 4.45 (m, HÀC (17) (24)); 135.5 (C(3'), C(3'')); 129.0 (C(2'), C(2''), C(4'), C(4'')); 128.2 (C(5'), C(5''), C(6'), C(6'')); 126.6 (C(1'), C(1'')); 113.6 (C(1), C (5) (18) (14)); 79.6 (C(2)); 79.3 (C (1) .0 2,18 .0 3,7 .0 4,17 .0 5,15 .0 6,13 .0 8,12 .0 16,20 ]icosane (52a). To a soln.…”

Section: Scheme 16mentioning

confidence: 99%

“…Photoelectron (PE) and electrochemical (CV) studies, extended to derivatives such as the diesters 1b and 3b, furnished thermodynamically meaningful estimates of the conjugative (p-bis-homoaromatic) stabilization of these ions [7] [8]. Of the secodienes, only derivatives such as 2b were available for comparison (CV); the parent 2a, differently from 2b amenable to EPR and superacid-oxidation experiments, has evaded all efforts for its synthesis.…”

mentioning

confidence: 99%

“…In explorative experiments with oxirane as scavenger for generated HBr, the percentage of 58a was significantly raised at the expense of 52b and 57a. In case of diester 2b, the manifold of products present after total conversion was even larger ± the mass spectra of the crude, not separable material displayed ions of composition [C 20 H 13(14) Br 3 (CO 2 CH 3 ) 2 ] as highest masses, hence a lower degree of bromination than for 2a ± a consequence of the inductively (and sterically) deactivating influence of the ester groups [8] (Scheme 11). It should be noted that the primary homoallylic cation was efficiently captured as methoxy bromide 55a, when the bromination of 2a was performed in CH 2 Cl 2 /MeOH 1 : 1.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Secododecahedradienes - Syntheses, Reactivity, in-Plane Homoconjugated 3C/2e Cations, 4C/3e Radical Cations, andσ-Bishomoaromatic 4C/2e Dications?

Reinbold

Bertau

Voss

et al. 2001

HCA

Self Cite

View full text Add to dashboard Cite

Edgar Heilbronner in alter Verbundenheit (H. P.; H.-D. M.) zum 80. Geburtstag Secodecahedradiene 2a, featuring very proximate, perfectly syn-periplanar and significantly pyramidalized CC bonds, was synthesized as testing object for in-plane(s)-homoconjugational electron delocalization, starting from the available pagodane 15b. The response of 2a (and in part its diester 2b) ± in p,p-distance (average 3.08 ), olefinic pyramidalization (average 26.98), and p,p-split (PE, 1.15 eV) intermediate between disecododecahedradiene 1a and 1,16-dodecahedradiene 3a ± to selected 4p-reagents, electrophiles, and radicals was explored experimentally and by calculations. Intriguing multistep reaction sequences attest to the ease of competing stabilization pathways for the 3C/2e in-plane homoconjugated cationic intermediates. PE, CV, and ESR measurements and calculations (DFT) characterize the radical cation generated from 2a as in-plane homoconjugated 4C/3e-species 2a. , persistent in a Freon matrix, but only very shortly existent in solution (CIDNP). Consequently, NMR control of the two-electron oxidation in SbF 5 /SO 2 ClF did not disclose the s-bishomoaromatic dication 4C/2e (see 2a 2 ), but a bis-allylic dication 75 as persistent species. In support of 2a 2 as intermediate, evidence is presented for very limited kinetic protection offered by the secododecahedral framework to through H-cage s-homoconjugated cations.

show abstract

Section: Scheme 10mentioning

confidence: 52%

Section: Scheme 16mentioning

confidence: 99%

Section: Scheme 16mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Secododecahedradienes - Syntheses, Reactivity, in-Plane Homoconjugated 3C/2e Cations, 4C/3e Radical Cations, andσ-Bishomoaromatic 4C/2e Dications?

Reinbold

Bertau

Voss

et al. 2001

HCA

Self Cite

View full text Add to dashboard Cite

show abstract

[2.2.2.2]/[2.1.1.1]Pagodanes and [1.1.1.1]/[2.2.1.1]/[2.2.2.2]Isopagodanes: Syntheses, Structures, Reactivities − Benzo/Ene- and Benzo/Benzo-Photocycloadditions

et al. 2000

Self Cite

View full text Add to dashboard Cite

The established route to the [1.1.1.1]/[2.2.1.1]pagodanes (1, 2) has been applied to the construction of the homologous [2.2.2.2] and [2.1.1.1] skeletons (3, 7). Application of this synthetic scheme to the iso[1.1.1.1]/iso[2.2.1.1]/iso[2.2.2.2] structures (4−6) failed though; the crucial [6+6]benzo/benzo photocycloaddition step in the face-to-face benzo/benzo intermediates (26a and b) − in contrast to the corresponding clean [6+2]benzo/ene-photocycloaddition (27a Ǟ 36) − did not take place. A bypass involving a stereoelectronically less demanding [2+2]ene/ene-photocycloaddition proved rewarding when double Birch reduction was achieved with the benzo/benzo substrates (26a and b), giving 28a and b. Domino-type [4+2]/[4+2] cycloadditions to the thermally rather labile "benzene-cyclodimers" [33a and b, E a (33a) = 23.9 ± 1.5 kcal mol −1 ] allowed the subsequent completion of the isopagodane skeletons in standard manner. The attempts to convert the highly strained, yet thermally highly persistent, (iso)pagodanes (3−7) into one of the derived (iso)pagodadienes [A(AЈ), B(BЈ)] − the calculated energies (MMP2) are also

show abstract

σ-Bishomokonjugation (σ-Bishomoaromatizität) in 4C/3(2)e-Kationen - Voraussetzungen und Grenzen

et al. 2001

Self Cite

View full text Add to dashboard Cite

Mit dem Secododecahedradien 1, bei dem die Abstände dππ zwischen den C‐Atomen der beiden Doppelbindungen 2.90 und 3.20 Å und die Pyramidalisierungswinkel Φ 14.9 und 35.5° betragen, werden die geometrischen Voraussetzungen für σ‐homokonjugative (σ‐bishomoaromatische) Elektronendelokalisierung in 4C/3(2)e‐Kationen abgesteckt: Während das 4C/3e‐Radikalkation in Matrix beständig ist, tritt das 4C/2e‐Dikation in supersaurer Lösung bestenfalls als Zwischenstufe auf dem Weg zum stabilen Bisallyldikation auf.

show abstract

Electrochemical oxidation of [1.1.1.1]pagodanes, bisseco-, seco- and dodecahedra(di)enes: stability of caged 4c/3e radical cations and 4c/2e dications

Cited by 20 publications

References 38 publications

Secododecahedradienes - Syntheses, Reactivity, in-Plane Homoconjugated 3C/2e Cations, 4C/3e Radical Cations, andσ-Bishomoaromatic 4C/2e Dications?

Secododecahedradienes - Syntheses, Reactivity, in-Plane Homoconjugated 3C/2e Cations, 4C/3e Radical Cations, andσ-Bishomoaromatic 4C/2e Dications?

[2.2.2.2]/[2.1.1.1]Pagodanes and [1.1.1.1]/[2.2.1.1]/[2.2.2.2]Isopagodanes: Syntheses, Structures, Reactivities − Benzo/Ene- and Benzo/Benzo-Photocycloadditions

σ-Bishomokonjugation (σ-Bishomoaromatizität) in 4C/3(2)e-Kationen - Voraussetzungen und Grenzen

Contact Info

Product

Resources

About