Masahiko Kato, M. Mitsuda, T. Shibuya
Jul 1, 1991
Citations
0
Influential Citations
2
Citations
Journal
Bulletin of the Chemical Society of Japan
Abstract
6,7,12,13-Tetrahydro-7,12-methano-3H-cycloheptacyclodecene-3,14-dione has been synthesized starting from the [4+6]-cycloaddition product of the reaction of 3,4-bis(methylene)-7,7-dibromobicyclo-[4.1.0]heptane with tropone. The adducts were transformed to their epoxides, which were treated with trifluoroacetic acid to give the 3,14-dione. This was transformed to benzo[1,2:4,5]dicycloheptene-1,9-dione, bis(tropono)benzene, by two different methods: (1) by heating it with trichloroacetic acid and DDQ in toluene or (2) through bromination followed by heating in DMF. The 1,9-dione is protonated in coned sulfuric acid to give bis(hydroxytropylium) dication, while it is protonated mainly (>80%) on the C-9 carbonyl oxygen and less (<40%) on the C-1 carbonyl oxygen in deuteriochloroform containing trifluoroacetic acid.