Studies on heterocyclic analogs of azulene.VI. Cycloadditions of styryl-substituted aza analogs of azulene with dimethyl acetylenedicarboxylate

Studies on heterocyclic analogs of azulene.VI. Cycloadditions of styryl-substituted aza analogs of azulene with dimethyl acetylenedicarboxylate

Creators Abe Noritaka

Creators Nishiwaki Tarozaemon

8-[(E)-Styryl]-1-azaazulenes stereospecifically react with dimethyl acetylenedicarboxylate to form trans-7H-6a-azacyclobuta[j]cyclopent[cd]azulene (3), which undergoes thermal rearrangement into 3-[(E)-styryl]3H-2a-azacyclopent[cd]azulene and 3a,4-dihydro-3H-2a-azadicyclopent[cd, ij]azulene (7), or isomerization into 3H-2a-azacyclopenta[ef]heptalene by silica gel. Compound 7 is oxidized during the course of reaction to yield 11-oxo-2aH-7,10b-methano-2a-azacyclopenta[ab]cycloundecene, compound 3 forming 5a,6-dihydro-3H-2a-azadicyclopenta[ef, kl]heptalene upon reaction with acetylene. The formation of 3 could be accounted for in terms of a symmetry-allowed thermal [_π2_s+_π2_a+_π6_a] cycloaddition.

[ISSN]0009-2673

[NCID]AA00580132

https://doi.org/10.1246/bcsj.53.1406

[isPartOf] [URI]http://www.jstage.jst.go.jp/browse/bcsj/-char/en