Heck reaction of protected allyl alcohols with aryl bromides catalyzed by a tetraphosphanepalladium complex

A range of aryl bromides undergo a Heck vinylation reaction with a protected allyl alcohol in the presence of [PdCl(C3H5)](2)/cis,cis,cis-1,2,3,4-tetrakis(diphenylphosphanylmethyl)cyclopentane as a catalyst. The reactivity of these allyl alcohol derivatives using a variety of protecting groups has been studied. The best results in terms of substrate/catalyst ratio were obtained with a THP protecting group. In most cases, the major isomer obtained was the (E)-cinnamyl alcohol derivative. The reaction tolerates several functionalities, such as trifluoromethyl, methoxy, dimethylamino, acetyl, formyl or nitrile. Furthermore, this catalyst can be used at low loadings, even for reactions with sterically hindered substrates.