✦ LIBER ✦
1-Substituted 1,3-Dihydroisothianaphthen-2,2-dioxides: Preparation and Use as ortho-Quinodimethane Precursors in Intramolecular Cycloadditions. Preliminary communication
✍ Scribed by Wofgang Oppolzer; David A. Roberts; T. Geoffrey C. Bird
- Publisher
- John Wiley and Sons
- Year
- 1979
- Tongue
- German
- Weight
- 260 KB
- Volume
- 62
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
1,3‐Dihydroisothianaphthen‐2,2‐dioxide (1) was readily converted to the 1‐substituted sulfones 3 by deprotonation and subsequent electrophilic attack (Scheme 3 and Table). The appropriate 1‐alkenyl‐ and 1‐alkenoyl‐sulfones 3 on heating at 213° to 240° underwent SO~2~‐extrusion to give, via the non‐isolated (E)‐quinodimethanes II (Scheme 1), polycyclic products such as 4, 6 and 7 in good yields (Schemes 4 and 5). On the other hand, thermolysis of the 1‐alkenoyl‐1‐thioether sulfones 9 furnished mainly the isochromenes 10 (Scheme 6).