Kleine Ringe, 87. Suche nach alternativen Wegen zum Tetra-tert-butyltetrahedran; Synthese sterisch überladener Verbindungen
✍ Scribed by Maier, Günther ;Rang, Harald ;Emrich, Rolf
- Publisher
- John Wiley and Sons
- Year
- 1995
- Tongue
- English
- Weight
- 920 KB
- Volume
- 1995
- Category
- Article
- ISSN
- 0947-3440
No coin nor oath required. For personal study only.
✦ Synopsis
Small Rings, 87rll. -Search for Alternative Routes to Tetra-terf-butyltetrahedrae;
Synthesis of Sterically Overcrowded Molecules
Ketene 3 can be isomerized to tricyclopentanone 2 by treatment with silica gel. Thus, the yield of tetrahedrane 5 , which is formed upon irradiation of 2, has been improved. On the other hand, diazoketone 10 cannot be used as a precursor for 2. This failure is due to steric hindrance. For the same reason cyclobutadiene 4 is a very poor candidate for Diels-Alder cycloadditions.
Tetrahedran 5 ist durch Tieftemperaturbelichtung von Cyclopentadienon 1 zuganglich[21. Dabei tritt zunachst eine Uberkreuzaddition zum Tricyclopentanon 2 ein, das Kohlenmonoxid eliminiert und uber Cyclobutadien 4 in Tetrahedran 5 ubergeht. Hauptnebenprodukt der Belichtung ist Keten 3.