A synthesis of (±)-2-pupukeanone (4) is described in
which the pupukeanane skeleton is assembled
by means of intramolecular cyclization of tosylate 11 and
then the attachment of an isopropyl group
at the appropriate position of the tricyclic ring system. The key
intermediate 11 was constructed
via a sequence begining from readily available ketone 5 and
proceeding through bicyclo[3.2.1]ketone
8 by regioselective ring expansion.