79905-98-9Relevant academic research and scientific papers
Direct Aryloxylation/Alkyloxylation of Dialkyl Phosphonates for the Synthesis of Mixed Phosphonates
Huang, Hai,Denne, Johanna,Yang, Chou-Hsun,Wang, Haobin,Kang, Jun Yong
, p. 6624 - 6628 (2018/05/14)
A strategy for the direct functionalization strategy of inertial dialkyl phosphonates with hydroxy compounds to afford diverse mixed phosphonates with good yields and functional-group tolerance has been developed. Mechanistic investigations involving both NMR studies and DFT studies suggest that an unprecedented highly reactive PV species (phosphoryl pyridin-1-ium salt), a key intermediate for this new synthetic transformation, is generated in situ from dialkyl phosphonate in the presence of Tf2O/pyridine.
The Mechanistic Diversity of the Thermal and Photochemical Decomposition of Bis(phenylphosphonoyl)Peroxides: Concerted Polar, Homolytic and Electron-Transfer Processes. On the Reactivity of (Phenylphosponoyl)oxyl Radicals
Korth, Hans-Gert,Lommes, Petra
, p. 2419 - 2438 (2007/10/02)
The thermal and photochemical decomposition of the first bis(phenylphosphonoyl)peroxides, dioxybis (5), and dioxybis (6) has been studied in various solvents by 1H-, 13C-, and 31P-NMR spectroscopy, laser flash photolysis (LFP), and ESR spin-trapping experiments.Kinetic studies reveal at 20 deg C a ca. 270 times slower thermal decay for 5 than for 6, which primarily results from a lower A factor rather than differences in the activation energies.The thermal decay of 5 occurs predominantly by a novel, presumably concerted polar rearrangement with formation of a thermally unstable, mixed phosphonoyl-phosphoryl anhydride.Photolysis of 5 induces homolytical cleavage of the peroxy bond with release of oxyl radicals 7.Radical 7 is characterized by a broad, transient UV/Vis absorption spectrum in the 400 to >700 nm range (λmax ca. 580 nm), as has been demonstrated by 248-nm LFP of 5 in acetonitrile solution.The short lifetime of this absorption indicates an extremely high reactivity (in hydrogen abstraction and addition) of this electrophilic radical.The thermal and photochemical decomposition of peroxide 6 leads to a virtually identical product distribution, suggesting O-O bond cleavage to be the major initial reaction under both conditions.LFP at 248 and 308 nm of a solution of 6 in acetonitrile initially produces a weak, broad absorption at ca. 500 nm and stronger bands at 280 and 400 nm.The highly transient 500-nm absorption is assigned to the oxyl radical 8, the other bands are attributed to the phosphonoyloxy-substituted benzene radical cation 8Z.The formation of this species can be explained in terms of electron transfer in the first-formed oxyl radical 8 and/or the intact peroxide 6, followed by cleavage of the peroxy bond.The decay of 8Z is accompanied by the build-up of the absorption spectrum of a 1,4-dioxy-substituted biphenyl radical cation.Key Words: Oxyl radicals / Phosphonoyl peroxides / Laser flash photolysis /ESR-Spin trapping / Electron transfer
PHOSPHORORGANISCHE VERBINDUNGEN 96. DIE SELECTIVE VERKNUEPFUNG BIOLOGISCH WICHTIGER FUNKTIONELLER GRUPPEN MIT PHOSPHORORGANISCHEN SAEUREN
Horner, L,Gehring, R.
, p. 157 - 176 (2007/10/02)
Derivatives of phosphinic, phosphonic, and phosphoric acids of the general type R1R2P(O)X show selectivity in their reactions with nucleophiles RYH (R = n-C4H9; Y = O, NR or S) according the Eq. (1); the selectivity depends on the nature of the leaving group (X = Cl, F, CN, N3 or OC6H4NO2(p)) and the base used.The nature of the ligands R1 and R2, exert a comparatively minor influence on the reaction.Method: (a) The phosphylating agent R1R2P(O)X was allowed to react with mixture of two nucleophiles RYH and RY'H in competition (Reagent ratio 1:1:1).The product mixture (R1R2P(O)YR + R1R2P(O)Y'R was then analyzed. (b) Compounds of the type HY-CH2-CH2-Y'H (serine-n-butylamide L-cysteinmethylester) were reacted with the phosphylating agent R1R2P(O)X (reagent ratio 1:1) according the Eqs. (3) and (4) respectively.The products were isolated, identified and the yields quantitatively determined.Results: For X = F, CN, OC6H4NO2 (p), the O-ester is formed virtually exclusively.For X = Cl, only amides are formed.Azides (X = N3) show no selectivity.In competition reactions using n-butylamine and n-butylthiol, the organophosphorus chlorides (X = Cl) were found to be N-selective,, whereas the corresponding cyanides (X = CN) were S-selective.In competition reactions using n-butanol and n-butylthiol, the organophosphorus fluorides (X = F) p-nitrophenylesters (X = OC6H4NO2(p)) and cyanides (X = CN) were all O-selective.
