Saturated heterocycle-condensed diphenylisoindolones: Fused-skeleton tetrahydro-1,3-oxazines, oxazolidines and imidazolidines

The addition of benzene to cis-4-cyclohexene-1,2-dicarboxylic anhydride yielded c-2-benzoyl-t-5-phenyl-r-1-cyclohexane-carboxylic acid (72%), or in another reaction, the 4-phenyl isomer (67%). With bifunctional reagents, saturated tricyclic or partially saturated tetra- and pentacyclic hetero derivatives containing an isoindolone moiety were prepared. The cis --> hans isomerization in the ring closures is promoted by enolization and by the two close-lying phenyl groups. The stereostructures of the products were determined via H-1 and C-13 NMR spectroscopy.