Palladium-Based Hydroamination Catalysts Employing Sterically Demanding 3‑Iminophosphines: Branched Kinetic Products by Prevention of Allylamine Isomerization

A new allylpalladium triflate catalyst with a dimesitylphosphine moiety was synthesized, isolated, and characterized. The greatly increased steric bulk on the phosphine of this palladium catalyst inhibited product isomerization, which is often observed after hydroamination of terminal allenes with secondary amines. The considerably reduced rate of isomerization facilitated the isolation of many previously unknown branched allylamines, products that were inaccessible when using other, more active 3-iminophosphine palladium catalysts.