Synthesis and Stereochemical Aspects of 2,6‐Disubstituted Perhydroazulenes – Core Units for a New Class of Liquid Crystalline Materials

A novel approach for the synthesis of cis/trans‐fused perhydroazulenes 13–19 is reported. The stereochemistry of the derivatives of carbene addition products 9a–c/20–22, of the 2,6‐disubstituted perhydroazulenes 12a–c/23–25, and that of compounds 26–27 has been studied by single‐crystal X‐ray crystallography. The hydrogenation of the tropylidene to the perhydroazulene skeleton under various conditions is described. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)