Gas Chromatographic Investigation of Stereoisomeric Cyclotrideca‐1,5,9‐trienesUsing achiral phases of different polarity in capillary gas chromatography on the one hand and a chiral cyclodextrine phase on the other hand it is demonstrated, that a ring‐enlargement sequence starting from (E, E, Z)‐cyclododeca‐1,5,9‐triene yields five of the six theoretically possible isomeric cyclotrideca‐1,5,9‐trienes and (E, Z)‐trans‐bicyclo[10.1.0]trideca‐ 4,8‐diene. With all achiral phases only three of the isomeric trienes and the bicyclic isomer were separated from each other; (E, Z, E)‐ and (Z, E, Z)‐cyclotrideca‐1,5,9‐triene are eluated in only one (the fifth) peak, these isomers were separated on the cyclodextrine phase. Moreover, this chiral phase separates the ena