DIMETHYL CUBANE-1,4-DICARBOXYLATE

In the crystal, dimethyl pentacyclo[4.2.0.0(2,5).0(3,8).0(4,7)]octane- 1,4- dicarboxylate, C12H12O4, has crystallographic 2/m symmetry. The c arbonyl group takes an eclipsed orientation with respect to the skelet on bond C1-C3, as well as to the methoxy O2-C5 bond. The ester group i s tilted in the direction of the opposite C atom C3'' about its stagge red orientation relative to the skeleton bonds C1-C2 and C1-C2'. The v alence angles within the ester group, C4-O2-C5, O1-C4-C1 and O1-C4-O2, are expanded to 116.9 (2), 126.2 (2) and 123.5 (2)degrees, respective ly. These enlargements cause a narrowing of the bond angle O2-C4-C1 to 110.4 (2)degrees.