Aryl diethyl phosphate

Hydroxy groups on benzene rings can be replaced by NH2 groups if they are first converted to aryl diethyl phosphates. Treatment of these with KNH2 and potassium... 

Reductive removal of oxygen from aromatic rings can also be achieved by reductive cleavage of aryl diethyl phosphate esters. 

In the electrochemical reduction of aryl diethyl phosphates, the initial one-electron addition is to the aryl ring and this is concerted with expulsion of the diethyl phosphate anion leaving an aryl radical. Further electron addition and protonation leads to the reaction product in 43-73 % yields. Examples of this electro-... 

Despite the abovementioned advantages, the only application of this useful synthetic procedure appears to be the otherwise difficult conversion of phenols into amines via the aryl diethyl phosphates in overall yields in excess of 55% (cf. Scheme 3).S6 Even this potentially useful reaction does not appear to... 

Keywords phenol, diethyl chlorophosphonate, magnesia, phosphorylation, aryl diethyl phosphate... 

The resulting alkyl or aryl diethyl phosphates were selectively detected at the 10-25 ng level with the P-mode FPD. Similarly, Jacob et al (36) used dimethyl thiophosphinic chloride in the presence of excess triethylamine to convert primary aliphatic, aromatic and heterocyclic amines to the corresponding N-dimethyl-thiophosphinic amides. The excess reagent was easily removed by treating the reaction mixture with methanol-sodium hydrogen car-... 

Deoxygenation of phenols. The reduction of enol phosphates to alkenes by titanium metal (8,482) has been extended to reduction of aryl diethyl phosphates to arenes. Yields are in the range 75-95% reduction with lithium in liquid ammonia (1, 248) usually proceeds in low yield. 

Deoxygenation of phenols may be achieved by reduction of aryl diethyl phosphates with lithium or sodium in liquid ammonia." A recent application of the methodology is outlined in Scheme 43." The reaction works well with a variety of substituted phenols, but not with dihydric phenols or naphthols. The alternative reduction of aryl sulfonates has also been examined, but the limited solubility of these derivatives can present difficulties. 

Aromatic hydroxyl groups may be removed after transformation into an aryl diethyl phosphate, which can be electrochemically cleaved [49] ... 

The reduction of aryl diethyl phosphates to aromatic hydrocarbons (first reported several years ago) has been investigated further and foimd to be a convenient and reasonably general procedure giving consistently high yields. Reduction of the phosphorodithioate ester (49) with zinc and acid is reported to give a mixture of phosphate and phosphinothioite esters together with some... 

An efficient method for the deoxygenation of a phenol, predating the Musliner-Gates procedure, consists of the reaction of the phenol with diethyl phosphorochloridate. The resulting aryl diethyl phosphate ester is then hydro-genolyzed with sodium in liquid ammonia. ... 

DFT calculations on the alcoholysis (MeO ) and thiolysis (MeS ) of three aryl diethyl phosphates 4-X-C6H40P(=0)(0Et)2 (X = Me, H, Cl) and of triethyl phosphate (TEP) in the gas phase and in solution showed that (i) the alcoholysis of diethyl 4-chlorophenyl phosphate proceeded through a concerted mechanism, while an associative mechanism was observed for its thiolysis reaction (ii) the reactivity of diethyl phenyl and diethyl 4-methylphenyl phosphates were similar and reacted via an associative mechanism with both MeO and MeS (iii) for TEP, the alcoholysis and thiolysis reactions proceeded by an associative mechanism and (iv) thiolysis of the four triesters was less favourable than alcoholysis in the gas phase and in solution." ... 

Recently, arylstannanes were prepared both from phenols via the corresponding aryl diethyl phosphate intermediates [138,139] and from the trimelhylammonium salts of arylamines [140]. Phosphate anion and trimethylamine were used in the place of haUde anions as the leaving groups in the reaction. Interestingly, when haloanilines or halophenol derivatives were used as the precursors, disubstitution products were obtained as illustrated in Scheme 4.25 starting from a phosphate or an anilinium salt [138-140]. 

Nakamura, M., Ouchi, A., Miki, M., and Majima, T., Photochemical P-O bond fission of aryl diethyl phosphates by a resonant two-photon reaction. Tetrahedron Lett., 42, 7447-7449, 2001. 

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