(2+2)-Dimerization of unsaturated, highly pyramidalized dodecahedranes (Φ = 43–45°) is explored as a route to C40-cage molecules and non-classical ions derived thereby. The cycloadducts (X-ray structure) formed under vigorous conditions either in solution or in the solid phase above 300 °C did not undergo 2σ → 2π isomerization. The MS fragmentation patterns, in line with calculations (B3LYP/6-31G*)
From Pagodanes to Dodecahedranes - Search for a Serviceable Access to the Parent (C 20 H 20 ) Hydrocarbon ** **Dedicated to Professor W. von E. Doering on the occasion of his 80th birthday. H.P. very fondly remembers his two post-doc years at Yale University (1957–59).
novel SN2 pagodane → dodecahedrane routes a preparatively potent access to the parent pentagonal dodecahedrane (2) was explored. The one-pot catalytic procedure (Pd/C/H2) starting from an eightfold functionalized secopagodane (14, C20H12Br6 (CO2 CH3)2) excells in shortness but, rather erratic (33–53%), falls out of the competition. The longer route via 1,6-dicarboxyl/dibromo dodecahedranes (35, 22)
Dodecahedryl Anion Formation and an Experimental Determination of the Acidity and C−H Bond Dissociation Energy of Dodecahedrane
作者:Katherine M. Broadus、Steven R. Kass、Thomas Osswald、Horst Prinzbach
DOI:10.1021/ja002588f
日期:2000.11.1
405.1 kcal/mol. In a similar manner, the electron affinity of dodecahedryl radical was measured (EA = 4 ± 2 kcal/mol). These results were combined in a thermodynamic cycle to afford the C−H bonddissociationenergy of dodecahedrane (BDE = 92 ± 3 kcal/mol), which is reasonably well reproduced (96.7 kcal/mol) at the MP2//HF level but leads to the suggestion that the reported heat of hydrogenation of dodecahedrene
"One-pot" substitution of the twenty hydrogen atoms in pentagonal dodecahedrane (C(20)H(20)) by OH, F, Cl, and Br atoms is explored. Electrophilic insertion of oxygen atoms with DMDO and TFMDO as oxidizing reagents ended, far off the desired C(20)(OH)(20), in complex polyol mixtures (up to C(20)H(10)(OH)(10) decols, a trace of C(20)H(OH)(19)?). Perfluorination was successful in a NaF matrix but (nearly