The mechanism of a diad prototropic rearrangement of hydrophosphorylic compounds

Racemization and transesterification of alkyl hydrogeno-phenylphosphinates

“…This prototropic equilibrium has already been shown to be strongly displaced toward the phosphine oxide form [21][22][23][24]. As shown within the next section, this fact is confirmed by our calculations.…”

“…As mentioned within a previous paragraph, the prototropic equilibrium involving MeHP 1 and its phosphonous acidic equivalent 3 has already been shown to be, in slightly different cases, strongly displaced toward the phosphine oxide form [21][22][23][24]. Our calculations lead exactly to the same result.…”

Synthesis and antimicrobial activities of some novel bis-pyrazole derivatives containing a hydrophosphoryl unit

“…Also, the signals of NH and H−P=O protons were displaced, presumably as a result of rapid protons exchange in two types of tautomeric equilibriums. The first type is tautomeric amide-imide equilibrium (i, ii, iii), while in the second type, hydrophosphoryl unit in solutions easily undergoes the tautomeric transition, providing it a unique combination of properties of pentavalent (λ 5 , σ 4 form) and trivalent (λ 3 , σ 3 form) phosphorus atom (phosphonate-phosphite i and iv) (Scheme 2) [24][25][26][27]. Also, the 13 C NMR spectrum of compound 3a displayed the carbon atoms of methyl and C=N groups at  14.7 and 157.2 ppm, respectively.…”

“…Abdel-Aziz et al / European Journal of Chemistry 2 (1) (2011)[25][26][27][28][29][30][31][32][33][34][35] …”

A Mechanistic Study on the Tautomerism of H-Phosphonates, H-Phosphinates and Secondary Phosphine Oxides

“…Despite the knowledge available on the interconversion of the P(V) and P(III) forms, further exploration and study was required in order to be able to avoid using any catalyst. Accordingly, a dyad form was proposed, where two >P(O)H derivatives form a dimeric complex and switch hydrogens [14,15,16]. Considering this mechanism, DFT (density functional theory) computations were performed for a small number of compounds in the gas phase, and the outcome was explained by the tunneling effect of the protons [14,15,16].…”