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“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

 

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