THE SYNTHESIS OF FUNCTIONALIZED CYCLOBUTANES EXO-ANNELATED TO THE BENZONORBORNANE SKELETON - THE CASE OF CYCLOBUTANONES AND CYCLOBUTANOL

The synthesis and spectral characterization of 2,2-dichlorocyclobutano ne 3, cyclobutanone 4 and cyclobutanol 5 annelated with benzonorbornan e are reported. Dichlorocyclobutanone 3 was obtained by the cycloaddit ion of dichloroketene with benzonorbornadiene. In the same experimenta l conditions the norbornenes annelated with exo- and endo-benzocyclobu tane moiety have not reacted with dichloroketene. The reductive remova l of the chlorine atoms with zinc and acetic acid gave cyclobutanone 4 . The same cyclobutanone was obtained by the oxidation of cyclobutanol 5 with chromium trioxide-pyridine complex. The compound 5 was obtaine d by the oxymercuration reaction of cyclobutene 9 with mercuric acetat e.