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A common feature of fluorescent sensing materials for detecting chemical warfare agents (CWAs) and simulants is the presence of nitrogen-based groups designed to nucleophilically displace a phosphorus atom substituent, with the reaction causing a measurable fluorescence change. However, such groups are also basic and so sensitive to acid. In this study we show it is critical to disentangle the response of a candidate sensing material to acid and CWA simulant. We report that pyridyl-containing sensing materials designed to react with a CWA gave a strong and rapid increase in fluorescence when exposed to Sarin, which is known to contain hydrofluoric acid. However, when tested against acid-free diethylchlorophosphate and di-iso-propylfluorophosphate, simulants typically used for evaluating novel G-series CWA sensors, there was no change in the fluorescence. In contrast, simulants that had been stored or tested under a standard laboratory conditions all led to strong changes in fluorescence, due to acid impurities. Thus the results provide strong evidence that care needs to be taken when interpreting the results of fluorescence-based solid-state sensing studies of G-series CWAs and their simulants. There are also implications for the application of these pyridyl-based fluorescence and other nucleophilic/basic sensing systems to real-world CWA detection. Chemical warfare agents and simulants are commonly detected with fluorescent sensing materials containing nitrogen-based groups, however these groups’ basicity can cause false positives in the presence of acids. Here, the authors disentangle the response of pyridyl-containing sensing materials to acid-containing and acid-free Sarin and simulants.

A phosphaguanidine [Me2NC(PPh2)=N i Pr], the analogous guanidine [Me2NC(NPh2)=N i Pr], and their hydrochloride (HCl) salts were prepared to study the influence of substituting a phosphorus atom for a nitrogen atom on the basicity of the two compounds and the bonding in their conjugate acids. The pK a values of both HCl salts were measured in acetonitrile by NMR titration. Surprisingly, the substitution of P for N has essentially no effect on basicity even though the geometry at that atom is changed. The presence of phenyl substituents in the protonated guanidine reduces the resonance in the CN3 core, whereas poor orbital overlap between P and C reduces the resonance in the N2CP core of the protonated phosphaguanidine. The neutral phosphaguanidine binds to a Cu(I) halide through both the Nimine and the P, which suggested that the basic N atom on the bound ligand may have little utility as a Brønsted base. Fortunately, however, a Cu(I) halide complex of the protonated phosphaguanidine is stable. Thus, the tendency of the basic N to bind to metals does not proscribe it serving as a metal-proximate Brønsted base.

The yet unknown 2-amino-substituted λ3 ,σ2 -phosphinines are phosphorus-containing aniline derivatives. Calculations show that the strong interaction of the π-donating NR2 group with the aromatic system results in a high π-density at the phosphorus atom. We could now synthesize 2-N(CH3 )2 -functionalized phosphinines, starting from a 3-N(CH3 )2 -substituted 2-pyrone and (CH3 )3 Si-C≡P. Their reaction with CuBr⋅S(CH3 )2 affords CuI complexes with the first example of a neutral phosphinine acting as a rare bridging μ2 -P-4e donor-ligand between two CuI centers. Our experimental and theoretical investigations show that 2-aminophosphinines are missing links in the series of known 2-donor-functionalized phosphinines.

Conformational analysis of tris(4-methylphenyl)phosphine and its oxide, sulfide, and selenide has been performed by the dipole moment method and DFT quantum chemical calculations at the B3PW91/ 6-311++G(df,p) level of theory. The title compounds have been found to exist in solution as a single symmetrical conformer with gauche,gauche,gauche orientation of the substituents on the phosphorus atom with respect to the P=X bond (X = LEP, O, S, Se).

Despite diamondoid phosphines have found many synthetic applications and are even available commercially the chemistry of chiral diamondoid phosphines remains largely unexplored. Aim . To develop the convenient preparative method for the preparation of sterically-congested P-stereogenic secondary diamodoidyl phosphines as potential organocatalysts and ligands in the asymmetric synthesis. Results and discussion . A convenient method for the synthesis of P-stereogenic diamondoid phosphines with high yields through the phosphorylation of hydroxydiamondoids in trifluoroacetic acid followed by the reduction of the corresponding asymmetric chlorophosphonates has been proposed. The secondary phosphines obtained form stable complexes with borane that can be used to separate diamondoid phosphines into enantiomers. Experimental part . The experimental procedures for the preparation of 1- and 4-diamantyl-1-adamantyl- and phenylphosphines were developed; the structures of new compounds were confirmed by NMR and HRMS spectral data. Conclusions . A number of P-stereogenic mixed diamondoidylaryl phosphines and the secondary phosphines containing exclusively diamondoid substituents has been prepared. A degree of steric bulkiness is determined by the combination of diamondoid substituents around a phosphorus atom where 1-diamantyl derivatives are the most sterically-congested. The compounds obtained are potential ligands in asymmetric catalysis. Received: 31.03.2020 Revised: 24.06.2020 Accepted: 27.08.2020

Thiophosphorus acids R1R2P(S)OH constitute an important class of organophosphorus compounds, in which the phosphorus atom is intrinsically chiral if R1 ≠ R2. In connection with a project aimed at the preparation of chiral thiophosphorus acids, various available literature methods were considered, but few fit the requirement of odorless reagents. Herein, the results of our studies on the synthesis of thiophosphinic acids are reported. Ultimately, two major approaches were selected: (1) the Stec reaction of phosphorus amides with carbon disulfide; and (2) the one-pot synthesis of thiophosphorus acids from H-phosphinates, an organometallic nucleophile, and quenching with elemental sulfur. An application to the preparation of a potential chiral phosphorus organocatalyst is also reported.

A propeller-like pyrene derivative of diphenyl-1-pyrenylphosphine (DPPP) is designed and synthesized. DPPP exhibits a unique photo-triggered AIE/ACQ transition with a remarkable third-order nonlinear optical signal change, which is proved to originate from the photo-induced oxidation of a phosphorus atom.

The reaction behavior of [Cp2Mo2(CO)4(μ,η2:2-P2)] (1) and [Cp''Ta(CO)2(η4-P4)] (2), respectively, towards the anions OH- and tBu- are reported. While the reaction of 1 with KOH gives the anionic complex [Cp2Mo2(CO)4(μ-PH2)]- (3) under a formal phosphorus atom abstraction, reaction with LitBu leads to the alkylation product [Cp2Mo2(CO)4(μ,η2:1-PPtBu)]- (4). The reactions of 2 with [IDipp-H][OH] ([IDipp-H]+ = 1,3-bis-(2,6-diisopropyl-phenyl)imidazolium) and LitBu yield [Cp''Ta(CO)2{η3-P4(O)H}]- (5) and [Cp''Ta(CO)2(η3-P4tBu)]- (6), respectively. Compounds 3, 4, 5 and 6 were comprehensively characterized by NMR spectroscopy and X-ray structure analysis.

A gold(I) complex with a 1,1′-binaphthyl-substituted diphosphene was synthesized and fully characterized. A phosphorus atom with a less-hindered binaphthyl group coordinates to a gold(I) moiety in ...

The proposed SN2 reactions of a hindered organophosphorus reactant with aliphatic and aromatic nucleophiles [Ye et al., Org. Lett. 19, 5384–5387 (2017)] were studied theoretically in order to explain the observed stereochemistry of the products. Our computations indicate that the reaction with the aliphatic nucleophile occurs through a backside SN2@P pathway while the reaction with the aromatic nucleophile proceeds through a novel SN2@Cl mechanism, followed by a frontside SN2@C mechanism. To the best of our knowledge, this is the first time that a SN2@Cl mechanism is reported. We also found that on reducing the bulkiness of substituents around the phosphorus atom, the backside SN2@P mechanism is preferred. The conclusions made from investigating the steric effect should help experimentalists to decide for the organophosphorus reactant to achieve the products of desired stereochemistry.

The synthesis and characterization of a range of bis(iminophosphoranyl)phosphide (BIPP) group 4 and coinage metals complexes is reported. BIPP ligands bind group 4 metals in a pseudo fac-fashion, and the central phosphorus atom enables the formation of d0–d10 heterobimetallic complexes. Various DFT computational tools (including AIM, ELF and NCI) show that the phosphorus–metal interaction is either electrostatic (Ti) or dative (Au, Cu). A bridged homobimetallic Cu–Cu complex was also prepared and its spectroscopic properties were investigated. The theoretical analysis of the P–P bond in BIPP complexes reveals that (i) BIPP are closely related to ambiphilic triphosphenium (TP) cations; (ii) the P–P bonds are normal covalent (i.e. not dative) in both BIPP and TP., The synthesis, characterization and computational analysis of a range of bis(iminophosphoranyl)phosphide (BIPP) group 4 and coinage metals complexes is reported. White phosphorus was used to install the central phosphorus atom.

Conformational analysis of tris(3-methylphenyl)phosphine and its chalcogenides has been performed by methods of dipole moments, IR spectroscopy, and quantum chemistry [DFT B3PW91/6-31G(df,p)]. In solution, these compounds exist as an equilibrium of conformers with gauche- and cis-arrangement of the substituents at the phosphorus atom relative to the P=X bond (X = lone electron pair, O, S, Se).

The first example of 16-membered aminomethylphosphines with pyridyl substituents on the phosphorus atom was synthesized as an RSSR isomer by covalent self-assembly in the system 1,3-bis[(pyridin-2-yl)phosphino]propane–formaldehyde–isopropylamine.

A mild and effective method for the synthesis of new tetraarylphosphonium zwitterions and salts containing methoxy and hydroxy groups in aryl substituents at the phosphorus atom was developed. The structure of phosphorus-containing betaines and phosphonium salts was obtained by NMR spectroscopy.

Different pentacoordinate spirophosphoranes were investigated by H/D exchange and NMR tracking experiments. The H/D exchanged site of spirophosphoranes was confirmed to be the N H bond instead of the P H bond according to the integration of the signal changes in proton-decoupled, proton-coupled 31P NMR and 1H NMR tracking experiments. The reactivity of N H bond at the spiroring of spirophosphoranes was explored by the rate constant of H/D exchange of different spirophosphoranes. The results demonstrated that the reactivity of N H bond of spirophosphoranes was influenced by steric hindrance and the species of substituent at phosphorus atom, and the electronic effect of the substituent was the main effect factor on the reactivity of the N H bond. The strong electron-withdrawing group at phosphorus resulted in more reactive N H bond of spirophosphoranes. These results are beneficial to further understand and explore the characteristics of pentacoordinate spirophosphoranes.

The structure and ion-selective properties of some 2-phosphorylphenols were studied. It was shown that, irrespective of the nature of the substituents on the benzene ring and on the phosphorus atom, these compounds exhibit potentiometric selectivity to cesium cation. The crystal structures of 2-(diphenylphosphoryl)-4-ethylphenol and 2-[(diphenylphosphoryl)methyl]phenol were established.

4-[(2-Diphenylphosphanylphenyl)methyleneamino]benzoic acid (HL) is obtained by the condensation of o-diphenylphosphinobenzaldehyde and p-aminobenzoic acid. The reaction of AgNO3 and HL affords complex [Ag2L2] · H2O (I). The structure of complex I is determined by X-ray structure analysis (CIF file CCDC 1575064), and its reflectance and luminescence spectra are studied. Binuclear complex I is a cyclic molecule in which each of two silver(I) atoms coordinates one phosphorus atom and one oxygen atom of two bridging anions L. Compound I is characterized by emission in a range of 430–740 nm at λexc = 340 and 395 nm.

2-(5-Methyl-2-phenyl-2H-1,2,3-diazaphosphol-4-yl)-4H-benzo[e]-1,3,2-dioxaphosphorin-4-one reacts with perfluorodiacetyl, 3,6-di(tert-butyl)-1,2-benzoquinone and phenanthrenequinone only with the participation of a three-coordinated phosphorus atom to form spirophosphoranes containing acyclic 5-methyl-2- phenyl-2H-1,2,3-diazaphosphol-4-yl substituent, whereas the interaction with tetrachloro-1,2-benzoquinone proceeds via expanding the six-membered heterocycle to the nine-membered one to form 2-(2-phenyl-2H-1,2,3-diazaphosphol-4-yl)-2,9-dioxo-4,5,6,7-tetrachlorodibenzo[d,h]-1,3,8-trioxaphosphonine.

Organophosphorus compounds with a phosphorus atom attached to a phenyl group and two organothio/organoseleno groups were synthesized using the rhodium-catalyzed insertion reaction of the PhP group of pentaphenylcyclopentaphosphine (PhP)5 with acyclic disulfides and diselenides. The method was applied to the synthesis of heterocyclic compounds containing the S–P–S group by the reaction of (PhP)5 and cyclic disulfides such as 1,2-dithietes, 1,2-dithiocane, 1,4,5-dithiopane, and 1,2-dithiolanes.

The effect of Buchwald-type ligands on the platinum catalyzed hydrosilylation of vinyl-terminated polydimethylsiloxane has been studied by differential scanning calorimetry of platinum catalyst-containing silicone compositions. Dialkyl(biphenyl-2-yl)phosphines bearing bulky substituents at phosphorus atom are efficient inhibitors of the catalytic hydrosilylation process allowing one to increase the pot-life of silicone composition and to prevent the decomposition of the Pt-based catalyst.

International audience; Proazaphosphatranes, also known as Verkade's superbases, have been investigated as ligands for gold(I). If the coordination to the gold center by the phosphorus atom suggests phosphine‐like behavior, gold(I)‐containing Verkade's superbase complexes could also be prepared from the weak conjugate acid azaphosphatrane by the formation of the corresponding silver complex and subsequent transmetalation to gold, similarly to the synthetic route used for complexes bearing N‐heterocyclic carbene ligands (NHCs). A competitive transmetalation experiment highlighted the higher lability of Verkade's superbases compared with NHCs. Furthermore, combined theoretical and experimental studies showed that they display strong σ‐donor ability, better than phosphines and similar to NHCs. Thus, some specific properties of both NHCs and phosphines are combined in Verkade's superbases, thereby providing a new approach to tuning the ligand properties of gold(I) complexes.

A facile synthetic method for unsymmetrical tertiary phosphine oxides is reported. Sequential treatment of phosphonodithioic acid S,S-di(p-tolyl) esters with two Grignard reagents enabled the stepwise introduction of different carbon substituents on the phosphorus atom. The chemical stability of dithioesters and monosubstituted thioesters has enhanced the utility of this method, rendering a wide range of organophosphorus compounds easily available.

Preparation of diastereomericamidosulfites or phosphonic acid amidoesters derived from a diastereomerically or enantiomerically pure phenol residue containing a chiral auxiliary is presented. The a...

The data on stereoselective reactions of achiral compounds of trivalent phosphorus with chiral nucleophiles (derivatives of secondary alcohols, amines, and amino acids) are analyzed and discussed. In certain cases, these reactions enable preparation of optically active aminophosphines and phosphinites, precursors in the synthesis of chiral organophosphorus compounds and phosphine ligands. The reactions are suitable for elucidation of mechanism and stereochemistry of nucleophilic substitution at trivalent phosphorus atom.

Is the broad mechanistic versatility of imidazole towards organophosphates (OPs), that has inspired many catalysts and sensors, beneficial? Herein, a thorough analysis is given seeking to unravel this puzzle. For OPs from the P=O family, imidazole attacks the phosphorus atom exclusively (N-phosphorylates). With the P=S family which are less reactive, an unusual N-alkylation predominates. Surprisingly, imidazole reacts with methyl parathion exclusively at the aliphatic carbon, whilst for the ethylated analogue parathion, imidazole reacts by two pathways: at both the phosphorus and aliphatic carbon, with predominance for the latter. The preference for the electrophilic center can be modulated by the pH. Overall, a mechanistic structure-related trend is observed: imidazole tends to prefer other electrophilic centers than the phosphorus for less reactive OPs. Moreover, this gives important insights concerning the challenging chemistry of imidazole alkylation and the outcomes for monitoring systems that depend on the detection of degradation products. Finally, a thorough comparison with the literature is presented seeking to understand how imidazole reacts towards various OPs. We suggest that the promiscuity of imidazole boosts up its versatility.

A series of phosphino triazoles are disclosed, within which, the phosphorus atom is appended by one, two or three triazole motifs. Gold(I) chloride complexes of the synthesised ligands were prepared and analysed by techniques including single crystal X-ray diffraction structure determination. SambVca (2.0) was used to determine percentage buried volumes. The effectiveness of these gold(I) chloride complexes to serve as precatalysts for alkyne hydration were assessed.

Since the development in the 1950's of 2-PAM (Pralidoxime), an antidote that reactivates organophosphate conjugated acetylcholinesterase in target tissues upon pesticide or nerve agent exposure, improvements in antidotal therapy have largely involved congeneric pyridinium aldoximes. Despite seminal advances in detailing the structures of the cholinesterases as the primary target site, progress with small molecule antidotes has yet to define a superior agent. Two major limitations are immediately apparent. The first is the impacted space within the active center gorge, particularly when the active center serine at its base is conjugated with an organophosphate. The reactivating nucleophile will have to negotiate the tortuous gorge terrain to access the phosphorus atom with its most nucleophilic form or ionization state, the oximate anion. A second limitation stems from the antidote crossing the blood-brain barrier sufficiently rapidly, since it is well documented that central acetylcholinesterase inhibition gives rise to cardiovascular and respiratory compromise. The associated hypoxia then leads to a sequelae of events, including poor perfusion of the brain and periphery, along with muscle fasciculation, tremors and eventually seizures. We consider both the barriers confronting and further achievements necessary to enhance efficacy of antidotes.

Dibenzo[b,e]phosphindolizines 1 were successfully synthesized by a ring-closing metathesis of benzo[b]phosphole chalcogenides 2a–2c with two vinyl tethers (for chalcogen analogs 1a–1c), and by a deselenization reaction (for lone-pair analog 1d). The structures, properties, and bowl inversion derived from a phosphorus atom were fully investigated.

The chemistry of transition metal compounds that contain a phosphorus atom acting as ligand, sometimes called “naked” phosphorus, started at the end of the last century. However, it is still an area of permanent interest and expansion, in which new examples of complexes with novel structural features are appearing in the literature. In this review, the phosphide complexes are classified based on the different coordination modes found in structurally characterised complexes for coordination numbers from 1 to 4 at the phosphorous atom. Structural aspects are discussed and, in some cases, the bonding patterns rationalised. Additionally to the structural analysis, data from 31P NMR spectroscopy, as a potent characterization tool, are also revised and briefly analysed.

A new method for reduction of tertiary phosphine oxides leading to the formation of tertiary phosphine-boranes has been developed. The BH3-THF/Ti(Oi-Pr)4 reducing system enables conversion of triaryl, diarylalkyl and trialkylphosphine oxides directly to their borane analogues in good to high yields. In contrast to the previously reported protocols, the presence of activating groups in the structure of starting material is not necessary for the reaction to occur. The reaction is highly stereoselective and proceeds with predominant retention of configuration at the phosphorus atom. A plausible mechanism of reduction of the P O bond by BH3-THF/Ti(Oi-Pr)4 has been proposed.

Bulky tris(carbene)borate ligands provide access to high spin iron(II) phosphido complexes. The complex PhB(MesIm)3FeP(H)Ph is thermally unstable, and [PPh] group insertion into a C–H bond of the supporting ligand is observed. An arrested α-hydride migration mechanism suggests increased nucleophilicity of the phosphorus atom facilitates [PPh] group transfer reactivity.

A new two-step synthesis of phosphonium salts from phosphine oxides using Grignard reagents is reported. This approach involves a cyclization of Z- dialkyl-(diaryl)[2-(5-chloro-2-hydroxyphenyl)-2-phenylvinyl]phosphine oxides under the action of sulfinyl chloride with the formation of 2,2-dialkyl(diaryl)-6-chloro-4-phenyl-2 H -1,2-benzoxaphosphinin-2-ium chlorides followed by ring opening under the action of organomagnesium compounds. The method was successfully applied to prepare a series of a new phosphonium salts bearing phenolic moiety with a wide range of substituents at phosphorus atom. Synthesized phosphonium salts shows high antibacterial and antifungal in vitro activity and low toxicity towards human red blood cell.

A simple and effective preparation of 2-hydrogeno-5 H -1,2-oxaphosphole 2-oxides 9a–b has been developed involving direct cyclization of H -phosphinic allenes. H -1,2-Oxaphospholenes 9a–b showed to be excellent building blocks for diversity oriented small chemical libraries. Then, reactivity of the cyclic H -phosphinates 9a–b was investigated through Pd(0) catalyzed arylation, Pudovik and three-component Kabachnik–Fields reactions. 5 H -1,2-Oxaphospholes are excellent heterocyclic platforms offering different opportunities to modulate the substituent directly bounded to the phosphorus atom.

We studied the reactions of manganese and rhenium phenylvinylidenes Cp(CO)2M═C═C(H)Ph (Mn1 M = Mn; Re1 M = Re) with HP(O)R2 (R = C6F5, Ph, and OEt) and HP(S)Ph2, which resulted in the selective formation of η2-E-phosphorylalkene complexes Cp(CO)2M{η2-E-H[R2(O)P]C═C(H)Ph} (Mn2, Re2 R = C6F5; Mn3, Re3 R = Ph; and Mn6, Re6 R = OEt) and Cp(CO)2M{η2-E-H[Ph2(S)P]C═C(H)Ph} (Mn5, Re5). The DFT/B3LYP(6-31G*) analysis showed the model reactions of Mn1 with HP(O)Me2 and HP(O) (OMe)2 to proceed via the initial transition state Cp(CO)2{Ph(H)C═C═}Mn···HO–PR2 (TS1) where the minor PA form HO–PR2 is hydrogen-bonded to the metal, followed by stereoselective (trans- to the phenyl group) addition of the PA phosphorus atom to the Cα-vinylidene atom, which defines both the rate of the process and the anti-Markovnikov structure of the reaction product. The reactions can proceed at a relatively low content of the reactive PA form.

1,4-Dichloro-3a,6a-diaza-1,4-diphosphapentalene reacts with sodium acetylacetonate to form an adduct of diacylcarbene with trivalent dicoordinated phosphorus. In solution this adduct dimerizes according to the head-to-head type. The phosphorus atoms undergo transformation from the hypervalent state (in the adduct), in which the lone electron pair on the phosphorus atom is not involved in the formation of additional bonds with this phosphorus(III) atom, to the pentavalent pentacoordinated and trivalent tricoordinated state (in the dimer).

A phosphole-fused porphyrin dimer, as a representative of a new class of porphyrins with a phosphorus atom, was synthesized for the first time. The porphyrin dimer exhibits remarkably broadened absorption, indicating effective π-conjugation over the two porphyrins through the phosphole moiety. The porphyrin dimer possesses excellent electron-accepting character, which is comparable to that of a representative electron-accepting material, [60]PCBM. These results provide access to a new class of phosphorus-containing porphyrins with unique optoelectronic properties.

Intramolecular cationic cyclization of β-hydroxyalkylphosphine oxides in the presence of an acid lead to the formation of fused bicyclic compounds with an incorporated phosphorus atom. Depending on the structure of the starting compound the formation of either phosphaindane or benzophosphorinane oxides has been observed. The key difference in the reactivity arises from the substitution pattern at the carbinolic carbon atom of β-hydroxyalkylphosphine oxide.

Even though seminal reports on phosphine catalysis appeared in the 1960s, in the last few decades of the past century trivalent phosphines were viewed primarily as useful ligands for transition-metal-mediated processes. The 1990s saw revived interest in using phosphines in organic catalysis, but the key advances in asymmetric phosphine catalysis have all come within the past decade. The uniqueness of phosphine catalysis can be attributed to the high nucleophilicity of the phosphorus atom. In typical phosphine-catalyzed reactions, nucleophilic attacks of the phosphorus atom on electron-deficient multiple bonds create different reactive ylide-type intermediates. When such structurally diverse zwitterionic species react with a variety of suitable substrates, new reaction patterns are often discovered and a diverse array of reactions can be developed. In recent years, substantial progress has been made in the field of asymmetric phosphine catalysis; many new reactions have been discovered, and numerous enantioselective processes have been reported. However, we felt that powerful and versatile phosphine catalysts that can work for a wide range of asymmetric reactions are still lacking. We therefore set our goal to develop a family of easily derived phosphine catalysts that are efficient in asymmetric induction for a broad range of phosphine-mediated transformations. This Account describes our efforts in the past few years on the development of amino acid-based bifunctional phosphines and their applications to enantioselective processes. Building upon our previous success in primary-amine-mediated enamine catalysis, we first established that bifunctional phosphines could be readily prepared from amino acids. In most of our studies, we chose threonine as the key backbone for catalyst development, and threonine-based monoamino acid or dipeptide bifunctional phosphines have displayed remarkable stereochemical control. We began our investigations by demonstrating the usefulness of our phosphine catalysts in aza-Morita-Baylis-Hillman (aza-MBH) and MBH reactions. We then showed the great power of amino acid/dipeptide phosphines in a wide range of [3 + 2] annulation processes, including [3 + 2] cycloaddition of allenoates to acrylates/acrylamides, [3 + 2] annulation of imines with allenoates, and [3 + 2] cyclization employing MBH carbonates and activated alkenes. By utilizing α-substituted allenoates and activated alkenes, we developed an enantioselective [4 + 2] annulation to access functionalized cyclohexenes. We also devised a novel enantioselective [4 + 2] annulation process by using α-substituted allenones for the construction of 3,4-dihydropyrans. With the use of β'-acetate allenoate, a [4 + 1] annulation process has been designed to access chiral spiropyrazolones. Another array of reactions that make use of the basicity of zwitterionic phosphonium enolate intermediates have been successfully attained, including the first phosphine-catalyzed asymmetric Michael addition, enantioselective allylic substitution of MBH carbonates by phthalides, and enantioselective γ-additions of prochiral 3-substituted oxindoles, 5H-thiazol-4-ones, 5H-oxazol-4-ones, and oxazol-5-(4H)-ones to 2,3-butadienoates. Bifunctional modes of action in our reported reactions have been supported by experimental results and theoretical studies. With the establishment of the new families of powerful amino acid-derived bifunctional phosphines, the discovery of new modes of phosphine activation, unknown reactions, and more enantioselective processes are well-anticipated.

O,O-Dialkyl S-(1,1-dimethyl-2-oxoethyl) dithiophosphates, 2-(dialkoxythiophosphorylthio)-substituted aldehydes with branched carbon groups, were obtained by hydrolysis of phosphoryl-containing iminium salts. The reaction with primary amines results in imines containing acetal group in different positions. Tri- and tetra-substituted perhydro-1,3-diazoles and oxazoles containing a phosphorus atom in the side chain were prepared by reacting the aldehydes with O,Nand N,N-dinucleophiles.

A facile method of synthesis of functionally substituted P(IV) derivatives―dialkyl(diaryl)(2-hydroxybenzyl) phosphine oxides―by the reaction of 2-ethoxy-2,3-dihydro[d][1,2]oxaphosphole 2-oxide with organomagnesium compounds, which allows wide variation of substituents on the phosphorus atom was developed.

The synthesis of gold(I) complexes of 2,5-diferrocenyl-1-phenyl-1 H -phosphole ( 1 ) is presented. Chloro(2,5-diferrocenyl-1-phenyl-1 H -phosphole)gold ( 3 ) has successfully been prepared by the reaction of 1 with AuCl(SMe 2 ) ( 2 ). Treatment of 2 with arylethyne (aryl = ferrocenyl, phenyl) using catalytical amounts of [CuI] and 1 equiv. of 1 gave arylethynyl-(2,5-diferrocenyl-1-phenyl-1 H -phosphole)gold 4a and 4b (aryl: a = ferrocenyl; b = phenyl). Compound [ μ -(1,4-phenylenedi-2,1-ethynediyl)]bis(2,5-diferrocenyl-1-phenyl-1 H -phosphole)digold ( 5 ) could be synthesized by a similar procedure using 0.5 equiv. of 1,4-diethynylbenzene. The electrochemical properties of 3 , 4a,b and 5 were investigated by cyclic and square wave voltammetry. In 3 , 4a and 4b each ferrocenyl unit shows one reversible redox event with redox separations of the ferrocenyl moieties in 2,5 position of approximately 260 mV. In 5 two redox events for the four ferrocenyl groups were observed. Spectroelectrochemical measurements of 3 , 4a and 4b reveal IVCT absorptions with intensities of 1100–1300 L mol −1 cm −1 and a full-width-at-half-height of ≈3650 cm −1 . In 5 two mixed-valent units are present per molecule and therefore, the intensity of the IVCT band is increased to 2700 L mol −1 cm −1 . Compounds 3 , 4a,b and 5 can be classified as moderately coupled class II systems according to Robin and Day. The complexation of the gold(I) fragment by the phosphorus atom leads to a decreased metal–metal interaction when compared to 1 .

Polarity of diselenophosphinates in benzene solution has been determined by second Debye method. We suggest that these compounds exist as a mixture of several conformers with cis and gauche arrangement of substituents at the phosphorus atom with respect to the P=Se bond.

A new effective synthetic route to the racemic phosphine oxides and phosphonium salts with a P-asymmetric center was developed based on the stepwise reaction of phosphacoumarins with organomagnesium compounds. A selective P–C bond formation was achieved on each step owing to the differences in reactivity of the exocyclic P–Cl or P–O bonds and endocyclic P–O bond of phosphacoumarins. It was found that the P(O)OMgX fragment of the phosphocoumarin salt does not hinder in the substitution reaction at the phosphorus atom accompanied by ring-opening and P–C bond formation.

9-Phosphaanthracene (dibenzo[b,e]phosphorin, acridophosphine) has attracted interest as one of the heavier acenes. Herein, we demonstrate an efficient synthetic process that provides air-tolerant 1,8-bis(trifluoromethyl)-9-phosphaanthracenes. The sterically encumbered and electron-withdrawing trifluoromethyl (CF3 ) groups are quite advantageous not only to stabilize the intrinsically unstable heavier unsaturated phosphorus atom but also to facilitate construction of the phosphinine skeleton based on a putative increase in aromaticity. The isolated 9-phosphaanthracenes allowed characterization of their fluorescence functionality and planar heteroanthracene frameworks. The crystal structures of 9-phosphaanthracenes are remarkably dependent on the aryl substituents at the 10 position; anthryl-substituted 9-phosphaanthracene showed unique polymorphs that induced different-colored crystals.

Synthesis of aryl phosphinates was achieved through cross-coupling reactions of aryl iodides with H -phosphinates catalyzed by nickel under mild conditions. The method was applicable to various aryl iodides and H -phosphinates having defined stereochemistry at the phosphorus atom.

4,5-Dimethyl-2-(2-oxo-1,2-diphenylethoxy)-1,3,2-dioxaphospholane bearing the carbonyl group at the γ-position to the phosphorus atom reacted with hexafluoroacetone to give regio- and stereoisomeric caged phosphoranes with phosphorus–carbon and phosphorus–oxygen bonds.

The NHC PH adduct IMes: PH was used to form one- and two-centered coordination compounds with tungsten and boron atoms using one or two lone pairs of phosphorus atom.

A 2,18-bis(diphenylphosphino)porphyrin ligand undergoes complexation with silver(I) chloride to afford a stable phosphine-silver complex. X-ray crystallographic analysis of the complex revealed a dimeric structure of a 1:2 adduct of the diphosphine and silver(I) chloride, where each phosphorus atom coordinates a silver atom. The four AgCl units construct a distorted cubic cluster with small metallophilic interaction. Variable temperature 31 P NMR study exhibited a slow ligand exchange process between 107 Ag and 109 Ag at high temperature.