Rhodium catalyzed anti-Markovnikov addition of triphenylphosphine to 1,3-dienes a novel method to separate pure (Z)-1,3-alkadienes from isomeric mixtures

Rhodium-catalyzed addition of triphenylphosphine and trifluoromethanesulfonic acid to (E)-1,3-dienes gives (E)-3-alkenylphosphonium salts in the anti-Markovnikov mode. The addition reactions to (E)-1,3-dienes proceed more rapidly than those to (Z)-1,3-dienes, which can be utilized to separate pure (Z)-1,3-dienes from isomeric mixtures.