Palladium-Tetraphosphine Complex Catalysed Heck Reaction of Vinyl Bromides with Alkenes: A Powerful Access to Conjugated Dienes

A wide variety of 1,3-dienes have been prepared by the Heck vinylation of vinyl bromides using [Pd(η3-C3H5)Cl]2/cis,cis,cis-1,2,3,4-tetrakis[(diphenylphosphino)methyl]cyclopentane (Tedicyp) as the catalyst precursor. Both α- and β-substituted vinyl bromides undergo the Heck reaction with functionalised alkenes such as acrylates, enones, styrenes or a vinyl sulfone, and also with nonfunctionalised alkenes such as dec-1-ene, leading stereoselectively, in most cases, to the corresponding E- or E,E-1,3-dienes in good yields. Furthermore, this catalyst can be used at low loading for several reactions.