928265-46-7Relevant academic research and scientific papers
Versatile and efficient synthesis of a new class of aza-based phosphinic amide ligands via unusual P-C cleavage
Tsai, Shih-Chung,Fu, Yaw-Shien,Liao, Ju-Hsiou,Yu, Shuchun Joyce
, p. 3007 - 3017 (2007/10/03)
A new class of bidentate, aza-based phosphinic amide ligands of the type RN(H)P(=O)(2-py)2 (2-py=2-pyridyl) was synthesized within minutes via a one-pot process including Staudinger reaction of an organic azide (RN 3) with 2-pyridylphosphines, followed by partial, unprecedented hydrolysis under loss of one aromatic substituent. The structure of the unusual-hydrolysis product H2C=CH(CH2)9N(H)P(= O)(2-py)2 (5a) was characterized by IR, 1H- and 31P-NMR, as well as by X-ray crystal-structure analysis (Figure). The tetrahedral P-atom was found to be surrounded by a trigonal-pyramidal arrangement of the substituents. To gain insight into the formation of these novel phosphinic amides, a series of intermediate iminophosphoranes, H 2C=CH(CH2)9N=P(Ar)n(2-py) 3-n (n = 0-3), compounds 1a-1f, were synthesized, and their hydrolyses were studied. All tested compounds followed the classical hydrolysis route of P=N cleavage under acidic conditions. Sequential hydrolysis to 5a-5d only occurred under either basic conditions or in wet MeCN as solvent. Notably, H2C=CH(CH2)9N=P(C6H 5)(4-MeO-2-py)2 (1c) was hydrolyzed at a much slower rate compared to its analogue 1b lacking the MeO group. On the contrary, the halogenated compounds H2C=CH(CH2)9N=P(4-X- C6H4)3 (1f,g) (X = F, Cl) were hydrolyzed at a notably faster rate relative to the non-halogenated congener 1e (X = H).
