Trisubstituted fZ -double bonds 5Z, 9Z and 13Z

Mainly two approaches are used, namely direct formation of the fZ carbon-carbon double bond by Wittig reaction or application of building blocks that already contain the required fZj-double bond. 

The generation of a trisubstituted double bond in a conjugated polyene by Wittig reaction yields mixtures of isomers with respect to the newly formed double bond. Subsequent chromatographic separation is necessary. 

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