A Method to Access Highly Functionalized Dibenzobicyclo[3.2.1]octadienones: Application to the Construction of the 6/6/5/6/6 Carbon Skeleton of Rubialatin A

The dibenzobicyclo[3.2.1]­octadienone
scaffold, which has been found
in naphthocyclinones, engelharquinones, rubialatin A, etc., has been
synthesized under mild transition metal-free conditions by aryne insertion
reaction with 2-keto-1,3-indandiones. The application of this methodology
has been demonstrated for the synthesis of the 6/6/5/6/6 scaffold
of rubialatin A. 1H NMR experimental studies confirm that
the reaction proceeds through the formation of benzocyclobutane followed
by a 7-member carbocycle ring.