Sterically Demanding Novel Triazole Based Tertiary Phosphines: Synthesis, Transition Metal Chemistry and Catalytic Applications

Abstract

AbstractSterically demanding 2,6‐dibenzhydryl‐4‐methylphenyl and 1,2,3‐triazole based tertiary phosphines, [Ar*{1,2,3‐N3C(Ph)C(PR2)}] (R=Ph, 3; R=iPr, 4) were obtained by the temperature‐controlled lithiation of 1‐(2,6‐dibenzydryl‐4‐methyl)‐5‐iodo‐4‐phenyl‐1H‐1,2,3‐triazole (2) followed by the reaction with R2PCl (R=Ph, iPr). Treatment of 3 with H2O2, elemental sulfur and selenium yielded chalcogenides [Ar*{1,2,3‐N3C(Ph)C(P(E)Ph2)}] (E=O, 5; E=S, 6; E=Se, 7). The reaction of 3 with [Pd(COD)Cl2] in 1 : 1 molar ratio, afforded dimeric complex [Pd(μ2‐Cl)Cl{Ar*{1,2,3‐N3C(Ph)C(PPh2)}‐κ1‐P}]2 (8), whereas the reactions of 3 and 4 with [Pd(η3‐C3H5)Cl]2 in 2 : 1 molar ratios produced complexes [Pd(η3‐C3H5)Cl{Ar*{1,2,3‐N3C(Ph)C(PR2)}‐κ1‐P}] (R=Ph, 9; R=iPr, 10). Treatment of 3 with [Pd(OAc)2] in 1 : 1 molar ratio afforded a rare trinuclear complex [{Pd3(OAc)4}{Ar*{1,2,3‐N3C(C6H4)C(PPh2)}‐κ2‐C,P}2] (11). Treatment of 3 and 4 with [AuCl(SMe2)] resulted in [AuCl{Ar*{1,2,3‐N3C(Ph)C(PR2)}‐κ1‐P}] (R=Ph, 12; R=iPr, 13). Bulky phosphine 4 was very effective in Suzuki‐Miyaura coupling and amination reactions with very low catalyst loading. Molecular structures of 3–5, and 8–13 were confirmed by single‐crystal X‐ray diffraction studies.