The Influence of Alkenes as π -Acidic Ligands in Pd-Catalysed Cross-Couplings

Recent advances in Pd-catalysed cross-couplings have exploited subtle changes (ligands, additives, reagent choice) that can influence both catalyst activity, selectivity and longevity. In the last few decades it has been noted that the addition of alkenes (olefins) as ligands for Pd can have a dramatic effect on these reactions. More recently, chemists have focussed on designing alkene-containing ligands to take advantage of their benefits. This review summarises the fundamentals of alkene ligands in Pd-catalysed cross-couplings. The development of alkene and mixed ‘hemilabile’ phosphine-alkene ligands is further highlighted.