Synthesis and properties of a mercapto[15]annulenone: a 14? diatropic annulene triply characterised by a fast chemical exchange, tautomerisation, and cis-trans-isomerisation
作者:Haru Ogawa、Masashi Yoshikawa、Hiroyuki Tanaka、Taiji Imoto、Izumi Miyamoto、Hidefumi Kato、Y?ichi Taniguchi、Yasuyoshi Nogami、Toshitaka Koga
DOI:10.1039/c39890000505
日期:——
Mercapto[15]annulenone (4) has been prepared from annulenone (2) as a tautomeric mixture with the keto-tautomer (5) in 65% yield; it was found that (4) proved to be diatropic and exists as a rapid equilibrium mixture of (4a) and (4b).
4:7,10:13-Diepoxy-1-aza[16]annulene and 3:6,9:12,15:18-triepoxy-2-chloro-1-aza-[18]annulene as the first examples of oxygen-bridged aza-[4n]- and -[4n+ 2]annulenes
title compounds were prepared by the Beckmann rearrangement of diepoxy[15]- and triepoxy[17]-annulenone oximes (2) and (11), respectively; 4:7,10:13-diepoxy-1-aza[16]annulene (5) exists as two tautomers, the keto form (5a) and the dipolar form (5b), forming a paratropic 16π system; 3:6,9:12,15:18-triepoxy-2-chloro-1-aza-[18]annulene (12) proved to be strongly diatropic (18π).
On irradiation, diepoxy[15]annulenone 1 and monobromo-diepoxy[15]annulenone 2 undergo an intriguing rearrangement, whereby all of the ether and carbonyl oxygens of 1 and 2 can travel freely and change their positions in the rings to give 15 position isomers in all.