4, 4-Dimethyl Effect. (4). The Conformation of α-Onoceradienedione in the Crystalline State

Abstract

Single crystals of α-onoceradienedione grown in methanol are orthorhombic, a=7.897, b=26.299, c=6.281 Å, U=1304.5 ų, D_e=1.117 g/cm³, Z=2 with space group P2₁2₁2. The structure, solved by the use of the MULTAN program, revealed that ring A (and also ring D) of the compound has a flattened chair conformation, the dihedral angle of 4β-methyl and the carbonyl plane being 97°.