One-Pot Synthesis of A PCsp3P-Type Pincer Complex via Double C-H Palladation of A Large Chelate Ring

Abstract The diphosphine proligand R2P(CH2)5PR2 (R= i-Pr) reacts with PdCl2 or Pd(PhCN)2Cl2 in CH2Cl2 to give the 2:2 adduct trans-{µ-ĸP,ĸṔ-R2P(CH2)5PR2}2Pd2Cl4 (1) featuring a 16-atom chelate ring, along with other uncharacterized species. Treating 1 with AgOTf or heating it in the solid state gave the PCsp3P-type pincer complexes {ĸP,ĸC,ĸP-(R2P(CH2)2)2CH}PdX (X: OTf, 2; Cl, 2-Cl). Complex 2 was also prepared via a one-pot route by refluxing a mixture of the proligand, PdCl2, and AgOTf in toluene. Complexes 1 and 2 have been characterized by NMR spectroscopy, elemental analysis, mass spectrometry and single crystal X-ray analysis.