Synthesis of Non-Conjugated Trienes via In Situ Hydrovinylation/Wittig Olefination of Unsaturated Phosphonium Salts

Abstract

A cobalt-catalysed 1,4-hydrovinylation reaction is successfully applied in a sequential three-component transformation of unsaturated phosphonium bromides, 1,3-dienes, and aldehydes leading to non-conjugated products with a 1,4-diene subunit in good to excellent yields. The hydrovinylation provides regioselectively diene structures with one exo double bond whereas the third double bond can be introduced via an in situ Wittig or Horner–Wadsworth–Emmons olefination leading to 1,4,7-trienes suitable for further double bond functionalisations.