The structures of two derivatives of bicyclo[3,3,1]nonane-2,4,9-trione. A natural product: clusianone, C33H42O4, and trimethylated catechinic acid, C18H20O6

The structures of two derivatives of bicyclo[3,3,1]nonane-2,4,9-trione were solved by direct methods. The structures of clusianone, C33H4204, and trimethylated catechinic acid, C1sH2006, were refined by standard least-squares techniques to weighted R(F) values of 0-038 and 0.046 respectively using diffractometer data. The two molecules are compared and unusually long C(sp3)-C(sp 3) bonds are discussed. Clusianone contains a 1"603 (4) A carbon--carbon bond.