2-Pyridyl-2-phospholenes: New P,N ligands for the palladium-catalyzed isoprene telomerization

2-(2-Pyridyl)-2-phospholenes are efficient ligands for the palladium-catalyzed telomerization of isoprene with diethylamine. Good selectivities for the tail-to-head or tail-to-tail aminoterpenes are achieved on optimization of the ligand substituents and of the reaction conditions, such as the nature of the catalyst precursor and of the solvent. Moreover, excellent catalytic activities are achieved on photochemical activation or addition of acidic co-catalysts.