- 作者: Pracht, Thomas ; Weber, Klaus ; Fritz, Hans et al.
- 作者服務機構: Institut fur Organische Chemie und Biochemie, Universitat Freiburg, Freiburg, Federal Republic of Germany
- 中文摘要: "Truncated" [ 1.1.1.1 ] pagodanes like the [ 1.1.0.0 ] and [ 0.0.0.0 ] homologues (3) and (E/sub Str/=146.1 to 171.5kcal/mol, MM2) are potential precursors of unusual unsaturated homoconjugated radical cations and .sigma.- bishomoaromatic dications. Attempts are presented toward the synthesis of (3)-starting out from [ 1.1.1.1 ] pagodane- 4,9-dione (9) and diaza [ 2.2.1.1 ] pagodadiene by cycloelimination (unsuccessful) and by Favorskii-type ring contraction methodologies. Control experiments with the model diketone (19) documented the limitations for.alpha.,.alpha.'-difunctionalization of (9) as the prerequisite for one-pot double Favorskii-type ring contraction. A de novo synthesis for such .alpha.,.alpha.'- disubstituted derivatives of (9) was not sufficiently expeditious to open a practical access to (3). Sequential double bridgehead hydroxylation of (9), successfully practiced with model (19), similarly suffered from inherent cage effects and allowed only limited yields of [ 1.1 .1.0 ] pagodanone, the intermediate on the way to (3).
- 英文摘要: --
- 中文關鍵字: Calculation; Favorskii Ring Contraction; Synthesis
- 英文關鍵字: 計算;Favorskii環收縮;合成