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This paper describes the photochemical and the thermal isomerization of s-cis (E,E) 1,1-diphenly-3,4-bis(trimethylsilylmethylene)-1-silacyclopentane ( 1a ). Under thermal conditions a 1,3-sigmatropic of the methylene hydrogen occurs, yielding the s-trans isomer ( 1b ). The photochemical irradiation of ( 1a ) at 300 nm for 1 h in deoxygenated benzene gives the corresponding s-cis ( E , Z ) isomer ( 1c ) and then the s-cis ( Z , Z ) isomer ( 1d ) after prolonged irradiation (3 h). There was no evidence for the formation of the corresponding cyclobutene resulting from the ring closure of the exocylic diene.

The diallylic phosphine-borane Ph(BH3)P(allyl)26, reacts with the zirconocene ‘Cp2Zr’ and gives the bicyclocomplex intermediate 7, characterized by 1H and 31P NMR. The electrophilic addition of H+, Br2, PhPCl2(BH3), Ph2PCl(BH3) leads to the corresponding stabilized phospholanes 8, 9, 11 and bicyclophospholane 10, whereas Ph2P(BH3)Li on 9 gives the boro(phospholane–diphosphine) 12. Under the same conditions, the tetraallylsilane (or germane) 13a–b leads to the spirometallacyclopentane 14a–b intermediates. After reaction with Br2, Ph2PLi(BH3) and PhPCl2(BH3), the racemic spirannic tetraphosphines 16a–b and the protected spirannic diphosphine 17b are obtained with a remarkable selectivity. Decomplexation reaction by Et2NH gives corresponding free phosphines 3′–17′.

The reactivity of red phosphorus towards aldehydes was investigated under basic and acidic media. It was demonstrated that the real phosphorylating agent involved in the reaction was phosphane (PH3) in basic media, and hypophosphorous acid (H3PO2) in acidic media. A convenient one-pot synthesis of (α-hydroxyalkyl)phosphinic acids from red phosphorus and aldehydes in basic media was realized under sonication. The same reaction under acidic media in the presence of hydriodic acid led to the corresponding phosphonic acids. The (α-hydroxyalkyl)phosphinic acids were readily prepared under sonication from hypophosphorous acid and aldehydes in the presence of catalytic amounts of hydrochloric acid. The mechanism of the addition reaction of PH3 to benzaldehyde was elucidated and shows the complexity of the reaction as a function of the experimental conditions.

The dipropargylic derivatives of Si, Ge, P, 1a–c, react with the zirconocene entity ‘Cp2Zr’ and give the intermediate bicyclocomplexes 2a–c characterized by 1H and 31P-NMR. The electrophilic addition of H+, Br2 leads to the corresponding exo dienic metallacyclopentanes 3,4. The cyclozirconation reaction with hetero-diallylic compounds 5a–d gives the metallacyclopentanes 7–15, after reaction with different electrophiles such as H+, PCl3, PhPCl2, Ph2PCl or Ph2PCl(BH3), Br2. The cyclozirconation reaction of diynes is stereoselective and leads to the E,E-exocyclic dienes whereas the selectivity of cyclozirconation of dienes depends on the substituents on the heteroatom.

In the diphosphirane series, the substitution of one aryl group (2,4,6-tri-tert-butyl‐phenyl) by a chlorine atom leading to the trans P‐chloro-diphosphirane via the cis isomer intermediate can be readily realized in chlorinated solvent under sonication or in the presence of gaseous hydrogen chloride in diethyl ether at room temperature.

The synthesis of ortho-substituted benzoic acid 3 from benzalphthalide 1 in the presence of ‘hydriodic acid—red phosphorus’ (HIaq/Pred) occurs via the formation of benzylphthalide 2 as reaction intermediate. Its preparation is optimized by use of the ‘supported reaction in dry media’ process (Silica/HIaq) under microwave irradiation for 8 min. The role of the red phosphorus in the reduction reaction is elucidated: it intervenes in a catalytic cycle by an oxido—reductive disproportionation with the liberated iodine, affording either hypophosphorous acid in aqueous media, or P2I4 in anhydrous media with concomitant regeneration of HI. Thus, the presence of Pred in the couple ‘HIaq/Pred’ allows recycling of the hydriodic acid and enhances its reducing efficiency.

The unsymmetrical diphosphirane 2a , obtained by addition of dichlorocarbene to the corresponding diphosphene ArPPTsi (Ar  2,4,6,-tri-tert-butylphenyl; Tsi  tris(trimethylsilyl)methyl) presents a structure with the shortest PP bond (2.117 A) ever observed in the diphosphirane series, and a torsion angle (Ar)CPPC(Tsi) close to 180° (177.0°). A shortening of intra- and extracyclic PC bonds, as well as of CCl bonds, is also observed comparative to the symmetrical diphosphirane 1a . Such short bonds can account for the special chemical behaviour of 2a . The anionic ring opening of the diphospharine 1c leads to the stable 1,3-diphosphaallyl anion 7c . The equivalence of the two phosphorus atoms and the existence of a PLi coupling constant of 41 Hz is an argument for a σ-allytic structure in solution.

The bis-allylic 1 and the bis-propargylic 6 derivatives react with the zirconocene “ZrCp2” and lead, after electrophilic addition, to the corresponding chiral trans heterocyclopentanes (MSi,Ge,P) 3–5 and bis-methylenecyclopentanes 8. New chiral diphosphine 9 is obtained starting from the intermediate complex 2 or the functionalized heterocyclopentane 4.

Ultrasound irradiation enhances the rate and improves the yield of the heterogeneous asymmetric Michael reaction without any modification of the enantioselectivity with respect to standard procedure. These improvements are assigned to ultrasonic mechanical effects.

The generation of phosphine PH 3 by alkaline hydrolysis of red phosphorus is realized. The subsequent alkylation of PH 3 by terminal alkenes and alkynes in basic media leading to the corresponding aliphatic and vinylic phosphine derivatives can occur by two-steps or one-pot reaction by a Michael-like reaction mechanism.

In order to evaluate the biological properties of new α-aminophosphonic acids 4a-g bearing a pyrrolic or thiophenic moiety, their synthesis via the corresponding esters 3a-g is carried out by two methods. The standard procedure leading to α-aminophosphonic esters 3 in good yields, requires heating of the neat reactants for several days. The sonochemical activation improves substantially the rate of formation of 3 and promotes the yields of the reaction. The rate enhancement for this homogeneous sonochemical reaction depends upon the temperature, the nature of the solvent, and the structure of the imine

The aminolysis of the hexachlorocyclotriphosphazene, N3P3Cl6 1, by the oxodiamines H2N-(CH2)3-O(CH2)2-O-(CH2)3 NH2 2 and H2N-(CH2)3-O-(CH2)6-O-(CH2)3-NH2 3 occurs immediately and regiospecifically in dry media leading to the corresponding spiranic cryptands 4 and 5, respectively. This process is an actual improvement (time, selectivity and workup) on the standard reactions.

The metallation reactions of the functionalized diphosphiranes 1a,b with the anionic metal transition complexes Na[(Cp)nM(CO)m] (M  Mo, W, or Co) afford σ- or π -diphosphaallyl complexes depending on the substituents of the intracyclic carbon atom. The same complexes are also obtained from their photochemical isomers, the 1,3-diphosphapropenes 2a,b. The complexes are thermally labile as shown by variable-temperature NMR spectroscopy. Upon heating, the σ-diphosphaallyl cobalt complex 3aC is irreversibly transformed into the π-complex 4aC. In contrast, with M  Fe and in toluene solution at reflux, reduced 1,3-diphosphapropenes 5a,b are obtained. Further, the gem-dihalogenated diphosphiranes 1c,d and their isomers 2c,d lead quantitatively to 1,3-diphosphaallene 6 under the same metallation conditions. The mechanism of the coordination reactions is discussed.

The metalation reactions of the functionalized diphosphiranes 1a–b with the anionic metal transition complexes (M = Mo, W, Co) afford the σ- or π- diphosphaallyl complexes (2 or 3, respectively) as function of the intracyclic carbon atom substituents. The thermal lability of these complexes is detected by variable-temperature NMR spectroscopy.

The reaction of saturated and unsaturated organomagnesium compounds with the monohalogenated diphosphiranes, 1a - b , and their isomers, the 1,3-diphosphapropenes, 2a - b , leads to a series of substituted 1,3-diphosphapropenes and 1,3-diphosphadienes 4 - 8 ( a - b ), but with the dihalogeno-derivatives 1c - d and 2c - d , it gives quantitative yields of 1,3-diphospha-allene 9 . The reaction occurs via an anionic ring-opening involving an allylic anion intermediate 11a - b , detected by 31 P NMR.

The symmetrical and unsymmetrical 1,3-diphospha-propenes 3 and 4 were obtained from the corresponding diposphiranes 1 and 2. The chemical behavior of these compounds has been studied. Phosphonium-phosphaalkenes 7a and 10a have been obtained in the reactions with aluminium trichloride. Whereas the symmetrical diphosphaallene 13 can be obtained by reaction of 1 or 3 with lithio compounds, the unsymmetrical diphosphaalene 14 cannot be prepared by a similar route. Reduction of 3a and 4a (obtained with a different conformation) by lithium aluminum hydride afforded phosphino-phosphaalkenes 17a and 18a (with a similar conformation); further dehydrochlorination with amines led to the symmetrical and unsymmetrical diphosphaalenes 13 and 14, respectively. The formation of allenes strongly depends on the conformation of the starting diphosphapropenes.

In the diphosphirane serie, whereas the fragmentation is a side reaction during the photochemical, thermal or cationic ring opening, the oxidation of the phosphorus lone pairs leads quantitatively to the corresponding phosphaalkenes, and the unstable phosphinidene.

Sonication improves substantially the rate of formation of diphosphene 1 with respect to standard procedures. The cyclopropanation of 1 using sonochemical generation of methylene or halogeno-carbenes constitutes an interesting alternative in the diphosphirane synthesis. Furthermore, ultrasonic effects in a chlorinated solvent allow the first substitution of a diphosphirane without ring-opening.

The cis/trans stereochemistry of diphosphiranes 1a–g, 2a, and 2h is investigated by MNDO calculations in terms of substituent effects on intracyclic phosphorus and carbon atoms. This approach is co...

The aminolysis of the hexachlorocyclotriphosphazene, N3P3Cl6 1, by the oxodiamines H2N-(CH2)3-O(CH2)2-O-(CH2)3 NH2 2 and H2N-(CH2)3-O-(CH2)6-O-(CH2)3-NH2 3 occurs immediately and regiospecifically in dry media leading to the corresponding spiranic cryptands 4 and 5, respectively. This process is an actual improvement (time, selectivity and workup) on the standard reactions.

The generation of phosphine PH 3 by alkaline hydrolysis of red phosphorus is realized. The subsequent alkylation of PH 3 by terminal alkenes and alkynes in basic media leading to the corresponding aliphatic and vinylic phosphine derivatives can occur by two-steps or one-pot reaction by a Michael-like reaction mechanism.

The dipropargylic derivatives of Si, Ge, P, 1a–c, react with the zirconocene entity ‘Cp2Zr’ and give the intermediate bicyclocomplexes 2a–c characterized by 1H and 31P-NMR. The electrophilic addition of H+, Br2 leads to the corresponding exo dienic metallacyclopentanes 3,4. The cyclozirconation reaction with hetero-diallylic compounds 5a–d gives the metallacyclopentanes 7–15, after reaction with different electrophiles such as H+, PCl3, PhPCl2, Ph2PCl or Ph2PCl(BH3), Br2. The cyclozirconation reaction of diynes is stereoselective and leads to the E,E-exocyclic dienes whereas the selectivity of cyclozirconation of dienes depends on the substituents on the heteroatom.

The role of base catalysts (CsNaX zeolite, hydrotalcite, triethylamine and pyridine derivatives) upon the regioselectivity of the Pudovik reaction is studied. The unexpected synthesis of stable 1,2-dihydropyridine phosphonate derivatives via a one-pot addition reaction under mild conditions is described.

The cis/trans stereochemistry of diphosphiranes 1a–g, 2a, and 2h is investigated by MNDO calculations in terms of substituent effects on intracyclic phosphorus and carbon atoms. This approach is completed by calculations of dipole moments. These results are compared to experimental dipole moment measurements of the synthesized diphosphiranes 3a–f.

The reaction of saturated and unsaturated organomagnesium compounds with the monohalogenated diphosphiranes, 1a - b , and their isomers, the 1,3-diphosphapropenes, 2a - b , leads to a series of substituted 1,3-diphosphapropenes and 1,3-diphosphadienes 4 - 8 ( a - b ), but with the dihalogeno-derivatives 1c - d and 2c - d , it gives quantitative yields of 1,3-diphospha-allene 9 . The reaction occurs via an anionic ring-opening involving an allylic anion intermediate 11a - b , detected by 31 P NMR.

Chiral (racemic) functional spirosilanes or -germanes, containing two (or four) stereogenic centers, were synthesized by selective cyclozirconation (or spirozirconation) of di- and tetraallylsilanes and di- and tetraallylgermanes.

Sonication improves substantially the rate of formation of diphosphene 1 with respect to standard procedures. The cyclopropanation of 1 using sonochemical generation of methylene or halogeno-carbenes constitutes an interesting alternative in the diphosphirane synthesis. Furthermore, ultrasonic effects in a chlorinated solvent allow the first substitution of a diphosphirane without ring-opening.

In the diphosphirane serie, whereas the fragmentation is a side reaction during the photochemical, thermal or cationic ring opening, the oxidation of the phosphorus lone pairs leads quantitatively to the corresponding phosphaalkenes, and the unstable phosphinidene.

The 1,3-diphosphapropenes exist in the form of two stable rotamers; their existence predicted by a theoretical study is verified experimentally using 31 P NMR method. The structural deformations of these two rotamers are connected to differentiate interactions between the P=C system and the phosphino group. These structural changes manifested through different NMR parameters would result in very different reactivities for these isolated systems

The symmetrical and unsymmetrical 1,3-diphospha-propenes 3 and 4 were obtained from the corresponding diposphiranes 1 and 2. The chemical behavior of these compounds has been studied. Phosphonium-phosphaalkenes 7a and 10a have been obtained in the reactions with aluminium trichloride. Whereas the symmetrical diphosphaallene 13 can be obtained by reaction of 1 or 3 with lithio compounds, the unsymmetrical diphosphaalene 14 cannot be prepared by a similar route. Reduction of 3a and 4a (obtained with a different conformation) by lithium aluminum hydride afforded phosphino-phosphaalkenes 17a and 18a (with a similar conformation); further dehydrochlorination with amines led to the symmetrical and unsymmetrical diphosphaalenes 13 and 14, respectively. The formation of allenes strongly depends on the conformation of the starting diphosphapropenes.

The structure of the functionalized trans-diphosphiranes 1a-e, obtained by reaction of halogenocarbenes with the trans-diphosphene is confirmed by X-ray diffraction. The photolysis of 1a-e lead to the functionalized cis- and trans-1,3-diphosphapropenes 2a-e as major products, via the diphosphiranyl and the diphosphapropenyl radical intermediates. The latter are characterized by ESR spectroscopy using the spin-trap method. The trans configuration of 2a is also confirmed by X-ray diffraction. The mechanism of the ring-opening, involving P-P bond rupture, is discussed

The cycloaddition reactions on Phosphorus Chemistry1 has allowed a new development of the three membered ring organophosphorus compounds. Starting from functionulized diphosphiranes obtained by action of carbenes on diphosphenes, we have studied their ring opening reactions leading to carbon insertion into P-P bond.

Publisher Summary This chapter states that the scope of the three-membered rings with two phosphorus atoms includes essentially the heterocyclopropanes, such as, diphosphiranes and diphosphirenes. Their chemistry is underdeveloped in comparison with its oxygen, nitrogen, and sulfur counterparts. Reference is made to the pioneering work of Baudler that allowed the detection of the first diphosphirane, and paved way for the development of various models. The chapter explores various methods developed for the synthesis of stable diphosphiranes and diphosphirenes. Their structural, stereochemical, and thermodynamic parameters are investigated by experimental and theoretical approaches. The chapter covers the literature until the middle of 1999. The synthesis section discusses diphosphiranes, polycyclic diphosphiranes, diphosphirenes and diphospherirenium salts, complexes of disphosphiranes, disphosphirene, diphosphirenium, and diphosphirenylium complexes. Physicochemical data and theoretical calculations are presented in details, along with an overview of the chemical properties of diphosphiranes, and disphospirenes and disphosphirenium salts. The chapter concludes that the different synthetic approaches have opened access to various stable or functionalized diphosphiranes and diphosphirenes. The observation drawn from their behavior is that under various conditions, the reactivity of diphosphiranes is dominated by the ring opening reactions involving a preferential P-P bond rupture.

The cycloaddition reactions on Phosphorus Chemistry1 has allowed a new development of the three membered ring organophosphorus compounds. Starting from functionulized diphosphiranes obtained by action of carbenes on diphosphenes, we have studied their ring opening reactions leading to carbon insertion into P-P bond.

The functionalized diphosphiranes 1 a–c, in presence of Lewis acid, undergo two kinds of reaction:the ring opening leading to the phosphenium-phosphonium ion 2a–c obtained according to an electrocyclic reaction and the fragmentation giving phosphaalkene 3a–c and phosphonium ion 4. The deprotonation reaction of 2a–c in hexane leads to phosphino-phosphaalkenes 6a–c.

The synthesis, with asymmetric induction, of chiral hexacovalent phosphorus anions, allows a polarimetric kinetic study of epimerization or racemization mechanism of these compounds which is shown to be irregular (acid catalyzed).

Different aspects of the reactivity of the diphosphene are presented: reactivity of the lone pair and/or reactivity of the double bond.

The phenomenon of second-order asymmetric transformation often encountered for optically active spirophosphoranes has made possible the isolation of the optically pure hexaco-ordinate phosphorus compound (2). It was possible to follow the epimerization of the hexaco-ordinate phosphorus atom by n.m.r. spectroscopy and polarimetry for dimethyl sulphoxide solutions. The values of ΔG‡(21.3 kcal mol–1) are very close to those observed for pentaoxyspirophosphoranes.

Resume Une vingtaine de spirophosphoranes nouveaux (Tableaux 1 et 2) ont ete prepares en faisant reagir les &alpha-aminoacides sur des composes du phosphore tricoordine possedant un groupement partant convenable. Dans le cas du compose 1i , un equilibre chaǐne-cycle P III P v a ete mis en evidence.

Diphosphiranes 3a - 3f are obtained by action of diazo derivatives and carbenes on the trans-diphosphene 1 . The structures are elucidated by spectroscopic methods. In all cases the cycloaddition reaction is stereoselective.

About twenty spirophosphoranes bearing a P–H bond have been obtained by the reaction of α-hydroxyacids or alkyl tartrates on tricoordinated phosphorus compounds. The stereochemistry is described. Intra- or extracyclic carbonyl groups, especially in the case of two identical ligands, increase the Lewis acid character of the phosphorus atom. Une vingtaine de spirophosphoranes a liaison P–H ont ete prepares en faisant reagir des α hydroxyacides ou des tartrates d'alcoyle sur des substrats a phosphore tricoordine convenables. L'etude stereochimique systematique de ces composes est decrite. La presence des groupements carbonyle a pour influence de renforcer le caractere d'acide de Lewis de l'atome de phosphore, notamment dans le cas des composes contenant deux ligands identiques, que le carbonyle soit intra ou extracyclique.

We have prepared phosphite ozonides 1b – 3b which are efficient and clean singlet oxygene generators at low temperature.

The ozonides of several phosphites in solution in dichloromethane have been reacted with some scavengers of singlet oxygen (1O2) like rubrene (2), tetraphenylcyclopentadienone (4), and 9,10-diphenylanthracene (6). These ozonides react on the scavengers (−47 °C 1O2. Results confirm that these ozonides can lead to the formation of 1O2. The absolute yield of 1O2 is 100% (ρ = 1). These results also confirm the high efficiency of the rubrene toward 1O2 (γ = 1) and the lower efficiency of the tetraphenylcyclopentadienone (γ = 0.46). However, the low value (γ = 0.3) for the efficiency of the 9,10-diphenylanthracene (4) is unexpected.

Resume A compound has been isolated whose elemental analysis, nmr and IR data are consistent with an equilibrium phosphoranide phosphite.

Condensing tartaric acid (R, R) and PCl3, we obtained oligomers 3 and cyclic dimer 4. Oxidizing these compounds by DMSO, we prepared hydroxyphosphoranes 6–9, while reaction of orthoquinones gave six-coordinated compound 10. Compound 4 reacts with triethylamine leading to an equilibrium between phosphoranide 5 and phosphite 5'. The more likely structure of oligomers is a sequence of TBP arranged on a helix, whereas dimers should have an emetic structure with pentacoordinated phosphorus atoms. These results are supported by nmr analysis, molecular weight and elemental analysis. All these compounds have strong optical activity. On the other hand, condensing PCl3 and malic or citric acids, we synthetized new functionalized spirophosphorans 2. En condensant l'acide tartrique (R, R) et PCl3, nous avons obtenu des oligomeres 3 et le dimere cyclique 4. En oxydant ces composes par le DMSO, nous avons prepare les hydroxyphosphoranes 6–9, tandis que la reaction des orthoquinones a donne le compose a phospho...

A phosphorus ozonides series was obtained by reaction of ozone on various phosphites (1a-13a). The oxidative addition of ozone leads to trioxophosphetane ring formation branched on pentacoordinated (1b-9b) or hexacoordinated (10b-13b) phosphorus. The stability and stereochemistry of these compounds were studied.