By PERSEPHONE CANONNE* and DENIS BBLANGER (Dkpartement de Chimie, Universitk Laval, CitS universitaire, Qukbec, Canada G1 K 7P4) ... Summary The reaction of the di( bromomagnesio) alkanes BrMg [CH,],MgBr and BrMg [CH,],MgBr with cyclic anhydrides produces spirolactones in one step in good yield. ... THE preparation of spirolactones has been the subject of much study in recent years and numerous procedures have been developed, including ...