Phosphorus substitution

The reaction of tetraphenylcyclopentadienone (tetracyclone) with dialkyl phosphites has invoked further interest. Miller has shown that reactions at 20 °C in the presence of sodium bicarbonate lead to products (35) and (36), with phosphorus substituted at carbon rather than oxygen. Quite different products (37) and (38) are obtained at 160 °C, although whether (38) is obtained from initial attack at oxygen or carbon is still unresolved. 

Tri-(l-naphthyl)phosphine is cleaved by alkali metals in THF solution. " Reaction with sodium gives the naphthalene radical-ion, with lithium the perylene radical-ion, and with potassium the radical-ion (22). Hydrocarbon radical-ion formation was thought to occur via naphthalene derived from the metal naphthalenide. E.s.r. spectra of further examples of phosphorus-substituted picrylhydrazyl radicals have been reported. ... 

The first chapter Heterophenes Carrying Phosphorus Functional Groups as Key Structures presents a detailed description of the recent advances made in this field. The recent studies of all-phosphorus-substituted aromatic compounds have revealed some unique properties of these heterocycles. 

In this review, synthesis, structure, and redox properties of phosphaquinoid compounds are described, keeping the contribution of thienoquinoid structures in mind in the first part. In the second part, synthesis and structure of phosphorus substituted thiophene and related compounds, especially tetraphosphoryl derivatives, are outlined (Scheme 3). 

Acknowledgments The author gratefully thanks Dr. F. Murakami and Mr. K. Adachi of Tohoku University for their exhaustive research work on phosphaquinoid compounds and phosphorus substituted heterophenes, respectively. He expresses thanks also to Professors. M. Yoshifuji and N. Morita of Tohoku University for encouragement. 

At low concentrations, defect clusters can be arranged at random, mimicking point defects but on a larger scale. This seems to be the case in zinc oxide, ZnO, doped with phosphorus, P. The favored defects appear to be phosphorus substituted for Zn, P n, and vacancies on zinc sites, Vzn. These defects are not isolated but preferentially form clusters consisting of (Pzn + 2V n). 

Phosphorus. Substituted phosphorus analogues of pyridine (phosphinines, A3-phosphabenzenes, also called phosphonins or phosphorins) were first prepared by Markl starting from pyrylium cations their chemical properties suggest that their aromaticity is lower than that of pyridine (e.g. phosphinine 186, Scheme 72).230-232 Molecular calculations for other six-membered jr-systems with planar tricoordinate phosphorus, such as phospininines 186 and 187, have evidenced their aromaticity (Scheme 72).156... 

An exceptional approach to phosphorus-substituted alkoxyallenes via isomerization of alkynes was introduced by Beletskaya s group. The treatment of 1-alkoxy-l-propynes 23 with l-halo-2,2-bis(trimethylsilyl)phosphaethen 24 furnished alkoxyallenes 25 (Scheme 8.9) [31]. 

Investigations by Vermeer and co-workers have shown that 3-substituted allenyl methyl thioethers 309 can be prepared by regioselective addition of an alkyl silver species to the terminal C=C bond of enyne sulfides 308 (Scheme 8.83) [172], Remarkably, this method can also be applied to the preparation of several allenyl-phosphines starting from the corresponding phosphorus-substituted alkynes. 

Synthesis and cyclization of phosphorus-substituted enyne-allenes. 

Scheme 20.24 Synthesis of phosphorus-substituted benzannulated enyne-allenes.

In contrast to A5-phosphorus-substituted diazo derivatives, which have been known for a long time,22 the synthesis of the first o -diazophosphine was reported as recently as 1985.23 This compound, namely the [bis(diiso-propylamino)phosphino](trimethylsilyl)diazomethane la, was obtained by treatment of the lithium salt of trimethylsilyldiazomethane with 1 equiv of bis(diisopropylamino)chlorophosphine. 

Flanigen, E.M. and Grose, R.W. (1971) Phosphorus substitution in zeolite frameworks. Adv. Chem. Ser., 101 (Molecular Sieve Zeolites-I), 76-101. 

This reaction proceeds with retention of configuration since the absolute configuration of the (-l-)-complex has been shown to be by X-ray analysis. Analogously, phosphorus substituted carbonyls react with germanes... 

Phosphorus-Substituted Organometallic Compounds From Phosphine Oxides... 

Benzophosphorinanes have also been synthesized by many different methods. Three will be mentioned, two of them using phosphorus-substituted benzenes as starting materials (equations (12) and (13)) <51JCS4ll,63AG(E)153,75JOC3763>. 

Photodecomposition of phosphorus-substituted oxirans provides a useful route to phosphonocarbenes.64... 

The vertical electron affinities of N5 and the phosphorus-substituted cations are given in Table 6. Most cations have electron affinities larger than 7.6 eV. Only the cations 5, 7, and 11 have electron affinities similar to that of Nj. They are candidates for formation of salts with very electronegative anions like AsFg, SbFj, or N5. The enthalpies of formation of the cations are given in Table 7. They vary between 221 kcal/mol for the PNP+--N2 complex 9 over 264 kcal/ mol for the 1,5-diphospha cation 11 to 354 kcal/mol for the linear cation 13. 

In a similar manner, phosphorus-substituted [3.3.1]phosphabicyclononanes 151 (R = dodecyl, cyclohexyl, phenyl) were obtained by the reactions of the 4-vinylcyclohexene 150 with the corresponding phosphines 149 in the presence of the azobis(isovaleronitrile) <2003W02003068786A1>. 

Molecular sieves50 is the term first given to zeolites dehydrated by heating in vacuum at about 350°C. However, there are now other materials, such as phosphorus substituted zeolites, microporous silicas, and A1P04 frameworks the latter are made hydrothermally in the presence of quaternary ammonium salts, like zeolites. 

The first phosphorus substituted carbodiimide was synthesized by Kohler and Kotte in... 

The reaction of bis(tiimethylsilyl)carbodiimide with the P=N derivative 26 gives the [2+2] cycloadduct 27, which on long standing rearranges to the phosphorus substituted carbodi-imide 28P... 

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