Synthesis and Characterization of Pd-3

The synthesis of Pd-3 was similar to Pd-2: Ligand was first synthesized using the procedure according to the previously reported literature [10 (link)]. The solution of ligand (300 mg, 0.68 mmol) and (tmeda)PdMe₂ (171.8 mg, 0.68 mmol) in 1.4-dioxane (30 mL) was stirred for 24 h at room temperature. The white powder produced during the reaction was filtered and dried in a vacuum. After added to 150 mL of DMSO, the mixture was stirred at 65 °C until the white solids were all dissolved. Subsequently, the solvent was further removed to give a beige solid, which was washed 3 times with ethyl ether and dried in vacuum (350 mg, 80.8% yield) (Figures S1–S3). ¹H NMR (500 MHz, 298 K, CDCl₃, 7.26 ppm): δ = 8.19 (dd, 1H, aryl-H), 7.42 (t, 1H, aryl-H), 7.28 (m, 2H, aryl-H), 6.09 (s, 2H, aryl-H), 3.82 (s, 6H, OCH₃), 3.78 (s, 3H, OCH₃), 3.06 (s, 6H, dmso-H), 2.84 (m, 1H, cyclohexane-H), 2.32 (m, 1H, cyclohexane-H), 1.89 (m, 1H, cyclohexane-H), 1.74 (m, 1H, cyclohexane-H), 1.68 (m, 2H, cyclohexane-H), 1.49 (m, 2H, cyclohexane-H), 1.25 (m, 3H, cyclohexane-H), 0.36 (s, 3H, Pd-CH₃). ³¹P NMR (202 MHz, 298 K, CDCl₃, 7.26 ppm): δ = 23.64. ¹³C{¹H} NMR (125 MHz, 298 K, CDCl₃, 77.16 ppm): δ = 164.55 (C-OCH₃), 162.64 (C-OCH₃), 148.08 (C-SO₃), 132.88 (P-C(PhSO₃)), 130.24, 130.11, 129.75, 128.33, 98.29 (P-C(PhOMe₃)), 91.21, 55.64 (OCH₃), 55.49 (OCH₃), 41.33 (S-CH₃), 40.28 (P-CH), 32.64 (CH₂), 29.75 (CH₂), 27.47 (CH₂), 27.31 (CH₂), 26.15 (CH₂),−1.03 (Pd-CH₃).