The synthesis of methano-bridged bisdehydro [18]-, -[20]-, -[22]-, and -[24] annulenes

✍ Scribed by Juro Ojima; Emiko Ejiri; Tadahito Kato; Shigeyasu Kuroda; Shuji Hirooka; Mitsuo Shibutani

• Book ID: 104218640
• Publisher: Elsevier Science
• Year: 1986
• Tongue: French
• Weight: 253 KB
• Volume: 27
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)84558-x

✦ Synopsis

Title annulenes were synthesized by Wittig reaction of cyclohepta-1,3,5-triene-1,6-dialdehyde or its vinylogous dialdehydes with 3-methylpenten-2-yn-4-yltriphenylphosphonium bromide, followed by intramolecular oxidative couplings of the resulting acyclic compounds, and they proved to be diatropic or paratropic, corresponding to the number of peripheral n-electrons.

P number of multi-bridged annulenes have so far been synthesized, especially by Vogel. 1) However, the monomethano-bridged annulenes over 18membered ring have few precedents, ') although the mono;ythano-bridged aza[l7]-