Triazolyl-phosphole and triazolyl-azaphosphole: synthesis, transition metal complexes and catalytic studies.

Phosphole and azaphosphole derivatives with triazole functionalities, [CH{1,2,3-NCCHC(PPh)}] (L1) and [CH{1,2,3-NC(Ph)C(PPh)}] (L2) were synthesized by reacting [(CH)(1,2,3-NC = CH--Br-CH)] and [(-Br-CH)(1,2,3-NC = CHCH)] with BuLi followed by the addition of dichlorophenylphosphine. The reactions of L1 and L2 with an excess of 30% HO afforded phosphole oxides [CH{1,2,3-NCCHC(P(O)Ph)}] (L1O) and [CH{1,2,3-NC(Ph)C(P(O)Ph)}] (L2O) as white crystalline solids. Stoichiometric reactions of L1 and L2 with [Ru(η--cymene)Cl] in CHCl yielded [RuCl(η--cymene)(L1-κ-)] (1) and [RuCl(η--cymene)(L2-κ-)] (2), respectively. Similar reactions of L1 and L2 with [Pd(COD)Cl] and [Pd(η-CH)Cl] produced the corresponding complexes, -[PdCl(L1-κ-)] (3), -[PdCl(L2-κ-)] (4), [Pd(η-CH)Cl(L1-κ-)] (5), and [Pd(η-CH)Cl(L2-κ-)] (6). Treatment of L1 with [AuCl(SMe)] in dichloromethane afforded [AuCl(L1-κ-)] (7). Ruthenium complex 1 showed moderate to good catalytic activity towards benzylic C-H oxidation, and the proposed mechanism for the catalysis was supported by spectroscopic data.