Phosphorus Group Derivatives

Phosphines readily substitute triflates to give both linear and cyclic silyl phosphines whose preparative separation has been developed while (H3Si)3P is C3V and weakly associated at lOOK . LiP[Si(F)Bu-t2l2 possesses a dipolar cyclic structure without direct Li—P contacts, an 

The first phosphasila-alkene results from 2,4,6-Bu c,H.,PH., (ArPH-) 

Ph P=CPh, give the ethenylidenephosphine which also results from 274 

The structures of the phosphorus ylids XMs2P=C(SiR CH ) iR2 resulting from X2C(SiR2CH2)2SiR2 and Me2SiPMe2 show a flat chair conformation for R=X C1, and a boat one for R=Me,X Br. PCl cleaves the Si-C bond at the ylid carbon atom, while MeP(SiMe2)2 couples (Cl-Si)-C=PMe,Cl to give the diylid [(Cl,Si) C=PMe -]- and cyclic 

Me sKPBu ) jSiMe. exists as the threo-erythro isomer only, for 

Me3SiPPh2 gives the ylid complex (CO) MnPPh2C(OSiMe3)R with 

Allylphosphines H2C=CHCH2PHMMe3 (M=Si,Ge) result from the halide and phosphine in the presence of Et3N, and new silylphosphines have been prepared by the addition of Me3SiPH2 to dienes and vinylphos- 

Oxidising PhSb(SiMe3 2 in 1,4-dioxane or benzene gives solvated (PhSb)g which possesses a chair conformation, and 

---

Phosphatidic acids not only are intennediates in the biosynthesis of triacylglycerols but also are biosynthetic precursors of other members of a group of compounds called phosphoglycerides or glycerol phosphatides. Phosphorus-containing derivatives of lipids are known as phospholipids, and phosphoglycerides are one type of phospholipid. 

Phosphinamides are stable to catalytic hydrogenation, used to cleave benzyl-derived protective groups, and to hydrazine. The rate of hydrolysis of phosphinamides is a function of the steric and electronic factors around the phosphorus. This derivative has largely been used for the protection of amino acids and occurs few, if any, times in the general synthetic literature. 

Haloacetyl groups have also a synthetic potential. Thus, pesticidal (alkylthio)-vinyl esters of phosphorus acid derivatives have been prepared by the introduction and subsequent displacement of two chlorine atoms in the acetyl moiety attached to the furazan ring (Scheme 69) [73GEP(0)2144393]. 

Another important biochemical compound derived from adenine is adenosine triphosphate (ATP). ATP plays a critical role in supplying energy in organisms to support metabolism. ATP is a nucleotide similar to RNA. In ATP the base is adenine and the phosphorus group is a three-phosphoryl (P032 ) chain. 

Bicyclic bridged phosphorinane derivatives can be synthesized by different methods. When phenylphosphine is heated with cycloocta-2,7-dienone to 135 °C in the presence of polymerization inhibitors, e.g. hydroquinone, and the double Michael addition product is oxidized, the two crystalline syn and anti isomers (total yield 48-59%) are isolated. Separation by crystallization gives the pure compounds which can in turn be transformed at the carbonyl or the phosphorus group (equation 10) (75T33,76JOC589). 

Recently, Majoral et al. described the synthesis of a third-generation phosphorus-containing dendrimer possessing 24 chiral iminophosphine end groups derived from (2S)-2-amino-l-(diphenylphosphinyl)-3-methylbutane (Fig. 11) [32]. The dendritic catalyst was tested in allylic substitution reactions, using rac-(.E)-diphenyl-2-propenyl acetate or pivalate as substrates. The observed enantioselectivities were good to excellent (max. 95% ee) in all reactions. After completion of the catalytic reaction, the catalyst could be reused at least twice after precipitation and filtration. A slight decrease... 

Rees and co-workers have carried out an extensive study of the addition of tri-methylsilyloxy phosphorus(lll) derivatives (phosphites, phosphonites, and phos-phinites, generated in situ) to aldimines to yield a-aminoalkyl-phosphonates, phosphinates and phosphine oxides (respectively, the transferred /V-TMS group being lost during work-up). Competition experiments demonstrated that the addition to imines is faster than that to the parent aldehydes. They found that the presence of electron-withdrawing groups in the imine slows the reaction. 

Studies of the synthesis of phosphorus-containing derivatives of cellulose fall into two groups phosphorylation of cellulose with derivatives of phosphoric acids and phosphorous acids, respectively. Until recently, most studies have been of derivatives of cellulose and phosphoric compounds. There are a few publications reporting the synthesis of esters of phosphorous acids and cellulose, but the properties of these compounds have not been studied at all. However, esters ctf phosphorous adds and cellulose can be used for the preparation ctf ters of phosphoric adds and cellulose, which cannot be obtained by direct synttesis (or only with difficulty) by the reaction of the hydroxyl groups of the cellulose macromolecule with phosphorus-containing reagents. 

As intramolecular hydrogen abstraction from the backbone is not possible in this case, the above process is believed to originate from the cleavage of peroxy radicals formed by reaction of oxygen with phosphorus macroradicals derived from residual unreacted P-Cl groups in the phosphazene main chain (Scheme 6). 

A variety of carbonyl group derivatives of cyclopropenones have been reported. The reaction of diphenylcyclopropenone with phosphorus pentasulfide gives diphenylcyclo-propenethione (equation 62). The thione has also been prepared using thioacetic acid... 

A review on the chemistry of thio derivatives of trivalent phosphorus acids which covers the literature to 1986, includes a section on pentaco-ordinate phosphorus compounds derived from addition to a-diketones and unsaturated systems activated to nucleophilic attack by electron withdrawing groups. Chemical bonding in hypervalent molecules has been discussed and qualitative bonding concepts developed to supersede the dsp and d sp models. A review on the mechanism and stereochemistry of the Wittig olefination reaction inevitably includes a discussion of the equilibrium between betaine and 1,2-oxaphosphetane intermediates. A correction has been published to reference 19 of Chapter 2 in SPR14, Vol.21, concerning the Mitsunobu Reaction. ... 

---