Intramolecular cyclisations of dimeric bis-anhydride compounds have been in
vestigated, to help elucidate the biosynthesis of the nonadride family of c
ompounds. Short and efficient syntheses of these bis-anhydride compounds, t
ogether with their cyclisations to yield analogues of glaucanic and iso-gla
ucanic acid, are described herein. (C) 2001 Elsevier Science Ltd. All right
s reserved.