1.3- Dioxaphosphorinane, oxidation

Dioxaphosphorinane, oxidation, 804 Dioxasiletane, disihrane singlet oxygenation,... 

Dioxaphosphorinane oxide (16) is formed by interaction of benzal-dehyde with benzylbis(a-hydroxybenzyl)phosphine oxide [Eq. (14)] on prolonged heating in the presence of an acidic catalyst (75JOC2056). 

Stereoisomers adopt a chair conformation with equatorial substituents at carbon (forms A and B, respectively), dioxaphosphorinane oxide, and... 

Gluco- and galactopyranosides were reacted with phosphonic and phosphoric dihalides to provide dioxaphosphorinane oxides 73 and 74 as mixtures of the two phosphorus epimers, which were separated. A similar method was used to prepare oxathiaphosphorinanes 75 from the corresponding thiopy-ranoside. Dioxaphosphorinane sulfides 76 were prepared from phospho-nothioic dichlorides [RP(S)Cl2] or by oxidation of the corresponding P(III) precursor with sulfur. Finally, oxazaphosphorinane oxides and sulfides 77 were prepared similarly. ... 

Organophosphorus Derivatives. Neopentyl glycol treated with pyridine and phosphorus trichloride in anhydrous dioxane yields the cycHc hydrogen phosphite, 5,5-dimethyl-l,3-dioxaphosphorinane 2-oxide (2) (32,33). Compounds of this type maybe useful as flameproofing plasticizers, stabilizers, synthetic lubricants, oil additives, pesticides, or intermediates for the preparation of other organophosphoms compounds (see Flame retardants Phosphorus compounds). 

Conformational populations of cyanomethylphosphine oxides (136) have been estimated from dipole moments and indicate a preference for the tra/15-conformation. The moments of the o-, m- and p-chloro- and tolyl-derivatives of triaryl phosphites (137, Y = ) and triaryl phosphates (137 Y = O) indicate that the oxygen atom in the latter series causes the aryl rings to rotate further away from a position in which their planes all meet along the molecular symmetry axis. Conformational studies have also been carried out on the dioxaphosphorinanes. The moments of the isomeric series (138a) and (138b) were in the ranges 3.7—4.2 and 5.4—5.5 D respectively. ... 

Dioxaphosphorinanes (l)-(3) readily oxidize and add sulfur and selenium [78IZV1911 79DOK(244)610, 79IZV866, 79IZV2136,... 

Methyl-2,4,6-triisopropyl-l,3,5-dioxaphosphorinanes (27) have been obtained by the addition of methyl iodide to (26) (791ZV1863). The alkylation did not stop at the first stage. Together with the product of the addition of one molecule of methyl iodide, a product of dialkylation (28) was also obtained [Eq. (17)]. The addition proceeds in a nonstereospecific manner. Whereas the precursor substance exists as one stereoisomer, compound (26) is a mixture of two stereoisomers in a ratio of 30 70 (78DOK331). Stereoisomeric oxides and sulfides of (27) have been prepared. 

Triisopropyl-1,3,5-dioxaphosphorinane (26) and its sulfide react with chloral, p-fluorobenzaldehyde, and acetaldehyde [Eq. (18)]. In the latter case, the hydroxymethyl derivative (29) (R = Me) was obtained. The reaction with chloral and p-fluorobenzaldehyde does not stop at the addition stage, but proceeds further to form the oxides (30) (R = CCI3,p-F-C6H4) (81IZV2776). 

IZV1630 811ZV2803 82IZV127]. The mixtures have been separated into individual stereoisomers by fractional crystallization, distillation, and chromatography. Equilibrium is reached more rapidly with sulfides than oxides. 1,3,5-Dioxaphosphorinanes with P(III) isomerize through the intermediate formation of protonated forms. 

The initially obtained product undergoes isomerization and then the addition of phenyl azide to the phosphorus atom takes place. It is proposed that the oxidative imination does not depend on the steric effects of substituents. Actually, the interaction of 5-phenyl-2,4,6-triisopropyI-1,3,5-dioxaphosphorinane, existing as a mixture of three stereoisomers, gives with phenyl azide a mixture of three stereoisomers of 5-phenyl-5-phenylimino-2,4,6-triisopropyl-l,3,5-dioxaphosphorinane (83IZV2550). 

Unlike 1,3,5-dioxaphosphorinanes the relative population of the con-former with the axial phenyl group at phosphorus decreases in 1,3,5-diazaphosphorinanes both for P(III) and for P(IV) compounds. Conformational analysis of 5-phenyl-1,3,5-diazaphosphorinanes and their oxides, sulfides, and selenides showed that the conformational equilibrium shifted toward the conformer with the axial phenyl group on changing from P(III) to P(1V) derivatives. The same conclusion made for 5-phenyl-l, 3,5-dioxaphosphorinanes, but it is contrary to that made for 1-phenyl-phosphorinane-4-ones and their derivatives (83MI1). 

On studying a series of ammonium 1,3,2,5-dioxaborataphosphorinane oxides (111), the dependence of the tautomeric equilibrium position on amine basicity was analyzed. The equilibrium position was estimated from chemical shift values of bis(oxymethyl)phenylphosphine oxide with 8 3IP of 35 ppm being used as a model of an acyclic form and 5-Ph-5-oxo-1,3,5-dioxaphosphorinane (107, R = H) with 8 3IP of 6 ppm used as a model of a cyclic compound. The chemical shift values (111, X = 0, R = H) and dissociation constants (pKa) of conjugate acids for amines are presented in Table V. 

Calculation of EM. The reference intramolecular reaction is nucleophilic attack by the anion of a carboxylic acid of pK, 3.15 on 2-phenoxy-l,3,2-dioxaphosphorinan-2-oxide. The rate constant for this reaction can be calculated as 7.67 x 10-10 dm3 mol 1 s-1 at 39° using the formula derived by Khan and Kirby (1970), and allows the direct calculation of the EM for the corresponding intramolecular reaction (COO-—P3—6n of A.5.5). The EM is assumed to be the same for the corresponding endocyclic reaction of the diphenyl ester anion (A.5.6), and has been shown not to differ significantly for endocyclic and exocyclic displacements (Bromilow etal., 1972)... 

Ethyl methyl ethylphosphonothionate (94 X = S) and the 4-methyl-l,3,2-dioxaphosphorinans (95 X = S R = OMe or NMe2) are oxidized with 90% H202 to the phosphoryl analogues with net retention of configuration phosphine sulphides, in contrast, are oxidized with inversion and racemization.64... 

BTSP also converts the thioxophosphoryl function to the oxophosphoryl function with inversion of configuration at P. For example, oxidation of tra .y-2-thio-2-chloro-5-methyl-1,3-dioxaphosphorinane 41 by BTSP in the presence of AICI3 gives the cw-isomer of the corresponding product of the oxygenation accompanied by less than 5% of the trans-isomer 42 (equations 64). P(III) esters can also be stereoselectively oxidized by BTSP, as demonstrated by the transformation of 2-chloro-4-methyl-l,3-dioxaphosphorinane to its oxygen derivative (equation 65)58. 

Die aus Methanphosphonsaure-difluorid und ot-D-Glucopyranosiden herstellbaren, am P-Atom epimeren l,3,2-Dioxaphosphorinan-2-oxide konnen getrennt und sukzessive mit Phenyl- bzw. Ethyl-magnesiumbromid in R- und S-Ethyl-methyl-phenyl-phosphanoxid umgewandelt werden (5%)232 ... 

Dioxaphosphorinan 2-(2-Chlor-ethoxy)-5-ethyl-4-propyl- -2-oxid XII/2, 337... 

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