Zwitterionic phosphonium ligands: synthesis, characterization and application in telomerization of 1,3-butadiene.

Novel zwitterionic phosphonium alkylsulfonate ligands are chemoselectively synthesized from N-heterocyclic phosphines and cyclic sulfones in one step in good to excellent yields. Their in situ generated palladium complexes showed high productivity in the industrial telomerization of 1,3-butadiene with methanol. Optimal results are obtained in the presence of cyclohexyl-substituted ligands under mild conditions and at metal loadings as low as 0.001 mol%.