Conformation of (±)-19,20-cyclopodocarpa-8,11,13-trien-19-one

Abstract

The conformation of (±)-19,20-cyclopodocarpa-8,11,13-trien-19-one (1b) has been determined by X-ray diffraction. Ring A assumes a distorted chair conformation while ring B, adjacent to the aromatic ring, takes up a distorted boat conformation. Crystals are monoclinic, space group P2₁/c, with a= 8.41(2), b= 7.40(2), c= 21.04(6)Å, β= 94.0(4)°, and Z= 4. The structure has been solved by direct methods from visually estimated photographic data, and refined by least-squares calculations to R 0.109 for 985 observed reflections.