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Synthesis and Ring-Opening Metathesis of Tetraalkoxy-Substituted [2.2]Paracyclophane-1,9-dienes

✍ Scribed by Dr. Chin-Yang Yu; Dr. Madeleine Helliwell; Dr. James Raftery; Prof. Michael L. Turner

Publisher
John Wiley and Sons
Year
2011
Tongue
English
Weight
456 KB
Volume
17
Category
Article
ISSN
0947-6539

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✦ Synopsis

Abstract

Tetraalkoxy‐substituted [2.2]paracyclophane‐1,9‐dienes can be prepared in three steps from dithia[3.3]paracyclophanes. A mixture of pseudo‐geminal and pseudo‐ortho diastereomers is produced and the pure compounds can be separated by fractional crystallization. The solid state structures of these diastereomers reveal strongly distorted aromatic rings consistent with high levels of ring strain. Reaction of these diastereomers with the second generation Grubbs catalyst shows that only the pseudo‐geminal isomer can be ring opened to give cis,trans‐distrylbenzenes. The origin of this selectivity is discussed and the photoisomerization of the as‐formed cis,trans‐product to the all trans isomer is demonstrated.

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ChemInform Abstract: Nazarov Cyclization
ChemInform Abstract: Nazarov Cyclization of Bis([2.2]paracyclophane-1,9-dienyl) Ketone: First Synthesis of a Bis([2.2]paracyclophane)-Anellated Cyclopenta-1,4-diene.
✍ H. A. BUCHHOLZ; A. DE MEIJERE 📂 Article 📅 2010 🏛 John Wiley and Sons ⚖ 28 KB 👁 1 views

Nazarov Cyclization of Bis ([2.2]paracyclophane-1,9-dienyl) Ketone: First Synthesis of a Bis([2.2]paracyclophane)-Anellated Cyclopenta-1,4-diene. -The anellated cyclopentanone derivatives (II) and (III) can be obtained by Nazarov cyclization of the ketone (I). (III) is successfully transformed into