Diastereoselective addition of α-substituted α-amino-H-phosphinates to imines using Yb(OTf)3 as an efficient Lewis acid catalyst

Potential chemical transformation of phosphinic acid derivatives and their applications in the synthesis of drugs

The chemical transformation of phosphinic acid is a well-considered mature area of research on account of the historical significant reactions such as Kabachnik-Fields, Mannich, Arbuzov, Michaelis-Becker, etc. Considerable advances have been made over last years especially in metal-catalyzed, free-radical processes and asymmetric synthesis using catalytic enantioselective. As a result, the aim of this synopsis is to make the reader familiar with advances in the approaches of phosphinic acids toward the synthesis of highly functionalized and valuable buildings blocks. Another purpose of this survey is to provide the current status of the applications of phosphinic acids in the synthesis of drugs.

Development of Biologically Active Compounds on the Basis of Phosphonic and Phosphinic Acid Functionalities

Phosphonic and phosphinic acids, especially α-heteroatom-substituted ones, possess unique structural and physical features which enable them to act as hydrotically stable analogs to biological phosphates in biological processes. They also act as mimetics in the transition state of the protease-induced hydrolysis of dipeptides. The first half of this review focuses on selected new synthetic methods developed by our research group for the stereoselective synthesis of α-heteroatom-substituted phosphonic and phosphinic acid derivatives, including modified nucleotide analogs and phosphinyl dipeptide isosteres. In the latter half, this review summarizes the utility of difluoromethylenephosphonic acids and phosphonic acid esters in the development of enzyme inhibitors against protein tyrosine phosphatases, sphingomyelinases, purine nucleoside phosphorylases and thrombin. The enzyme inhibitors developed were used as probes to elucidate signal transductions and the mechanisms of enzyme actions. The findings of the studies are briefly described.

Extensive analysis of N-H...O hydrogen bonding in four classes of phosphorus compounds: a combined experimental and database study

The N-H...O hydrogen bond is the characteristic interaction in the crystal structures of N-benzyl-P-phenyl-N'-(p-tolyl)phosphonic diamide, C₂₀H₂₁N₂OP or (C₆H₅)P(O)(NHCH₂C₆H₅)(NHC₆H₄-p-CH₃), (I), diphenylphosphinic 1-methylpropylamide, C₁₆H₂₀NOP or (C₆H₅)₂P(O)[NHCH(CH₃)(C₂H₅)], (II), (S)-1-phenylethylammonium N-[(S)-1-phenylethyl]phenylphosphonamidate, C₈H₁₂N⁺·C₁₄H₁₅NO₂P^- or [S-(C₆H₅)CH(CH₃)NH₃][(C₆H₅)P(O){S-NHCH(CH₃)(C₆H₅)}(O)], (III), and (4-methylbenzyl)ammonium diphenylphosphinate, C₈H₁₂N⁺·C₁₂H₁₀O₂P^- or [4-CH₃-C₆H₄CH₂NH₃][(C₆H₅)₂P(O)(O)], (IV). This article focuses on the N-H...O hydrogen bonds by considering the structures of (I), (II), (III) and (IV), and reviewing their analogous compounds, including 43 (C)P(O)(N)₂, 102 (C)₂P(O)(N), 31 (C)P(O)(N)(O) and 96 (C)₂P(O)(O) structures, deposited in the Cambridge Structural Database (CSD). For the structures with a (C)P(O)(N)₂ segment, only neutral hydrogen bonds were found in the CSD. The other three classes of compounds included both neutral and `charge-assisted' hydrogen bonds, and the (C)₂P(O)(O) structures were particularly noticeable for a high number of cation-anion compounds. The overall tendencies of N...O distances in neutral and cation-anion compounds were compared. The N-H...O hydrogen-bond angles were also analyzed for the four classes of phosphorus compounds.