ABSTRACT
Kolbe cross-dimerization has also been studied stereochemically mainly from a practical aspect with the aim of preparing stereoisomeric long-chain olefins from saturated and unsaturated carboxylic acids [265,266]. The stereoisomeric ratio (Z / E: 2.4-10.1) is influenced by current density (100-250 mA cm-2) and temperature (-16 to 60°C). Although the pure Z acid was used as the starting material, the product was not the pure Z olefin but a mixture with the E olefin. This indicates that stereoisomerization around the double bond at the y-position can occur in the Kolbe-type decarboxylation. Hawkes and coworkers [263] also reported that cross-coupling between acetic and 4-tbutylcyclohexanecarboxylic acids proceeded nonstereoselectively.
