89683-62-5Relevant academic research and scientific papers
P A G O D A N E - AN UNDECACYCLIC C20H20-POLYQUINANE
Fessner, W.-D.,Prinzbach, H.,Rihs, G.
, p. 5857 - 5860 (1983)
Pagodane, a highly symmetrical undecacyclic C20H20-polyquinane, is efficiently synthesized starting from "isodrin".
- and Pagodane Dications: Frozen Two-Electron Woodward-Hoffmann Transition-State Models
Prakash, G. K. Surya,Krishnamurthy, V. V.,Herges, Rainer,Bau, Robert,Yuan, Hanna,et al.
, p. 7764 - 7772 (1988)
- and pagodanes 1/21 were oxidized in SbF5/SO2ClF at -78 deg via two-electron removal from the central cyclobutane ring to give the dications 9 and 24, respectively.Dication 9 is also formed selectively by two-electron oxidation of a diene valence isomer of 1(19) and by ionization of the Br2 adduct of 1 (18).The unique dication 9 is stable at ambient temperature for hours, while the bishomologous 24 rearranges to a bisallylic dication, probably 28, even at -78 deg C.The tight structural prerequisites for the stability of such dications are further substantiated by the observation that from several related cyclobutanoid cage compounds 29-34, when exposed to the same oxidative conditions, no distinct dications could be observed.On the basis of 1H and 13C NMR chemical shift criteria, supported by pertinent SCF-MO calculations, the dications obtained are considered as novel four-center/two-electron delocalized bishomoaromatic species, which resemble two-electron Woodward-Hoffmann transition states and owe their unprecedented character to their specific rigid farmework.The reliability of the calculations in handling cage molecules of this type and size is evaluated in a comparison with structural data provided by single-crystal X-ray structure determinations for - and pagodanes 1/21 and dimethoxy product 16 obtained from quenching experiments with methanol.
The Pagodane Route to Dodecahedranes Unsaturated (Hyperstable) and Saturated Bissecododecahedranes
Murty, Bulusu A. R. C.,Pinkos, Rolf,Spurr, Paul R.,Fessner, Wolf-Dieter,Lutz, Georg,et al.
, p. 1719 - 1740 (2007/10/02)
In bissecododecahedra-1,10(11)-dienes, the syn-periplanar and unusually proximate arrangement of the ? bonds is responsible for extraordinary physical properties such as strong through-space homoconjugation, low oxidation potentials, and a special reactivity pattern.In pursuit of route B to dodecahedranes, the hyperstability predicted (MM2) for these bissecodienes and the related monoenes has been experimentally verified only for the latter in their resistance towards catalytic hydrogenation.Non-hydrogenative saturation of (3,8-difunctionlized) bissecodienes (3, 8, 13) and monoenes (4, 9, 14) becomes increasingly hampered due to the increased steric congestion on the more spherical molecular surfaces but can be achieved in "high-driving-force" reactions .In contrast, cycloadditive four-, five- (73), and six-membered (76) ring annulation again is limited to monoadditions.The half-cages in the bissecododecahedrane structures provide for remarkable steric steering and protection 2-, lack of hydrazone formation from ketones 58, 89, resistance of syn-bis(acid chloride) 86 towards hydrolysis. Key Words: Bissecododecahedranes, saturated, unsaturated / Homoconjugation / Hyperstability / Addition reactions / Cage effects
