The crystal and molecular structures of 3,3,6,6-Tetramethylbicyclo[2.2.1]heptane-2,5-dione and 6,6-Dibromo-1,3,3-Trimethylbicyclo[2.2.2] octane-2,5-dione

The X-ray crystal structures of two bicyclic diketones have been determined. 3,3,6,6-Tetramethylbicyclo[2.2.1]heptane-2,5-dione, C11H16O2 (A), is monoclinic,C2/c (No. 15), with cell dimensionsa=9.071(3),b=9.748(5),c=12.322(6)Å,β=110.15(3)°, andZ=4. The structure was determined by direct methods and refined toR1=0.065,R2=0.052 for 570 reflections. 6,6-Dibromo-1,3,3-trimethylbicyclo[2.2.2]octane-2,5-dione, C11H14Br2O2 (D), is orthorhombic,Pcab, …