Pd-catalyzed tandem bis-hydroaminocarbonylation of terminal alkynes for synthesis of N-aryl substituted succinimides with involvement of ionic P, O-hybrid ligand

Several novel ionic phosphines (L1–L4) with good robustness against water and oxygen were synthesized and characterized. The XPS analysis disclosed that L1 derived from Xantphos could serve as a P, O-hybrid ligand with P, O-chelation to Pd-center. Resultantly, L1 conferred to PdCl₂(MeCN)₂ high catalytic activity, excellent selectivity and good stability in the bis-hydroaminocarbonylation of alkynes for production of N-aryl substituted succinimides with the isolated yields of 57–90 %. The control experiments and the in situ high-pressured FT-IR analysis further confirmed that over L1-Pd(MeCN)₂Cl₂ catalytic system, the studied bis-hydroaminocarbonylation of terminal alkynes was a tandem reaction following Pd-H species (ν 1942 cm⁻¹⁾ mechanism.