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Light-Induced and Thermal π-Skeletal Rearrangement of Heptalenes with Retention of Configuration

✍ Scribed by Werner Bernhard; Paul Brügger; Peter Schönholzer; Roland H. Weber; Hans-Jürgen Hansen

Book ID
102856806
Publisher
John Wiley and Sons
Year
1985
Tongue
German
Weight
630 KB
Volume
68
Category
Article
ISSN
0018-019X

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✦ Synopsis

Abstract

It is shown that dimethyl 5, 6, 8, 10‐tetramethyl‐ (3) and 8‐ (tert‐butyl)‐5,6,10‐trimethylheptalene‐1, 2‐dicarboxylate (5), and their derivatives rearrange reversibly on irradiation or on heating to yield the corresponding 1,6,8,10‐tetramethyl‐ (4) and 8‐(tert‐butyl)‐1,6,10‐trimethylheptalene‐1,2‐dicarboxylate (6), and their derivatives by double‐bond shift (π‐skeletal rearrangement) via a transition state with D~2~ symmetry as the highest possible one. This follows from the fact that (−)‐(P)‐3 is photochemically as well as thermally rearranged to give (−)‐(P)‐4 i.e. the π‐skeletal rearrangement occurs with retention of configuration of the heptalene skeleton and without loss of optical purity.

📜 SIMILAR VOLUMES

σ-Skeletal-Rearrangement of Heptalenes:
σ-Skeletal-Rearrangement of Heptalenes: Thermal Transformation of Heptalene-1,2-dicarboxylates into Heptalene-1,3-dicarboxylates
✍ Werner Bernhard; Paul Brügger; John J. Daly; Gerhard Englert; Peter Schönholzer; 📂 Article 📅 1985 🏛 John Wiley and Sons 🌐 German ⚖ 968 KB

## Abstract It is shown that dimethyl heptalene‐1,2‐dicarboxylates undergo rearrangements at temperatures > 200° to yield the corresponding 1,3‐dicarboxylates, which are isolated as the more stable 3,5‐dicarboxylates. ^2^H‐ and ^13^C‐labelling experiments with dimethyl 7‐isopropyl‐5,10‐dimethylhept