“Truncated” Pagodanes — Synthesis of Functionalized [1.1.1.1] and [1.1.1.0]Pagodanes
作者:
Thomas Pracht,
Klaus Weber,
Hans Fritz,
Lothar Knothe And,
Horst Prinzbach,
期刊:
Journal of the Chinese Chemical Society
(WILEY Available online 1994)
卷期:
Volume 41,
issue 1
页码: 1-26
ISSN:0009-4536
年代: 1994
DOI:10.1002/jccs.199400001
出版商: WILEY‐VCH Verlag
关键词: “Truncated” Pagodanes;De novo syntheses;Calculations;Favorskii ring contractions
数据来源: WILEY
摘要:
Abstract“Truncated” [1.1.1.1] pagodanes like the [1.1.0.0]and [0.0.0.0] homologues3 and 4 (EStr= 146.1 – 171.5 kcal mol−1, MM2) are potential precursors of unusual unsaturated homoconjugated radical cations and σ‐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 11 by cycloelimination (unsuccessful) and by Favorskii‐type ring contraction methodologies. Control experiments with the model diketone 19 documented the limitations for α,α′‐difunctionalization of 9 as the prerequisite for one‐pot double Favorskii‐type ring contraction. Ade novosynthesis for such α,α′‐disubstituted derivatives of 9(54) was not sufficiently expeditious to open a practical access to 3. Sequential double bridgehead hydroxylation of 9, successfully practized with model 19, similarly suffered from inherent cage effects and allowed only limited yields of [1.1.1.0] pagodanone 10
点击下载:
PDF
(3728KB)
返 回