Phosphorus Carbon Bond Formation Research Articles

Carbon–Phosphorus Bond Formation by Enantioselective Palladium‐Catalyzed Allylation of Diphenylphosphine Oxide

AbstractThe enantioselective Pd‐catalyzed allylation of diaryl‐substituted allylic carbonates and diphenylphosphine oxide was investigated. This method gave allylic diphenylphosphine oxides in yields up to 95 % with 97 % ee. Pd‐catalyzed allylation of (E)‐methyl allyl carbonates with diisopropyl phosphonate was also examined.

ChemInform Abstract: Phosphorus—Carbon Bond Formation: Palladium‐Catalyzed Cross‐Coupling of H‐Phosphinates and Other P(O)H‐Containing Compounds.

Two generally applicable systems have been developed for the cross-coupling of P(O)H compounds with Csp2X and related partners. Palladium catalysis using a ligand/additive combination, typically either xantphos/ethylene glycol or 1,1′-bis(diphenylphosphino)ferrocene/1,2-dimethoxyethane, with diisopropylethylamine as the base, proved to be generally useful for the synthesis of numerous PC containing compounds. Routinely, 2 mol% of catalyst are employed (less than half the amount typically employed in most other literature reports). In most cases, excellent results are obtained with a variety of electrophiles (RX, where R=alkenyl, allyl, alkynyl, etc.). The full account of our studies is disclosed, including tandem hydrophosphinylation/coupling and coupling/coupling for doubly catalytic phosphorus-carbon bond formation. The methodology compares favorably with any existing literature report. The use of an additive appears to be a generally useful strategy to control the reactivity of phosphinylidene compounds.

Phosphinate Chemistry in the 21st Century: A Viable Alternative to the Use of Phosphorus Trichloride in Organophosphorus Synthesis.

Organophosphorus compounds are important in everyday applications ranging from agriculture to medicine and are used in flame retardants and other materials. Although organophosphorus chemistry is known as a mature and specialized area, researchers would like to develop new methods for synthesizing organophosphorus compounds to improve the safety and sustainability of these chemical processes. The vast majority of compounds that contain a phosphorus-carbon bond are manufactured using phosphorus trichloride (PCl3) as an intermediate. However, these reactions require chlorine, and researchers would like to avoid the use of PCl3 and develop safer chemistry that also decreases energy consumption and minimizes waste. Researchers have already proposed and discussed two primary strategies based on elemental phosphorus (P4 or Pred) or on phosphine (PH3) as alternatives to PCl3. However, phosphinates, an important class of phosphorus compounds defined as any compound with a phosphorus atom attached to two oxygens, R(1)R(2)P(O)(OR) (R(1)/R(2) = hydrogen/carbon), offer another option. This Account discusses the previously neglected potential of these phosphinates as replacements of PCl3 for the preparation of organophosphorus compounds. Because of their strong reductive properties, industry currently uses the simplest members of this class of compounds, hypophosphites, for one major application: electroless plating. In comparison with other proposed PCl3 surrogates, hypophosphorous derivatives can offer improved stability, lower toxicity, higher solubility, and increased atom economy. When their reducing power is harnessed to form phosphorus-carbon or phosphorus-oxygen bonds, these compounds are also rich and versatile precursors to organophosphorus compounds. This Account examines the use of transition metal-catalyzed reactions such as cross-coupling and hydrophosphinylation for phosphorus-carbon bond formation. Because the most important industrial organophosphorus compounds include compounds triply or quadruply bound to oxygen, I also discuss controlled transfer hydrogenation for phosphorus-oxygen bond formation. I hope that this Account will further promote research in this novel and exciting yet much underdeveloped area of phosphinate activation.

Facile Phosphorus–Carbon Bond Formation using a Tungsten-Coordinated Phosphirenyl Cation

Reaction of K2[W(CO)5] with Cl2PN-i-Pr2 in the presence of diphenylacetylene leads to the tungsten aminophosphirene complex [W(CO)5{P(N-i-Pr2)C(Ph)C(Ph)}] (1), which can be converted to the chlorophosphirene complex [W(CO)5{P(Cl)C(Ph)C(Ph)}] (2) by reaction with HCl. Chloride abstraction from 2 with excess AlCl3 leads to the tungsten-complexed phosphirenyl cation [W(CO)5{PC(Ph)C(Ph)}][AlCl4] (3). Compound 3 reacts with PPh3 to form a phosphoniophosphirene complex and undergoes electrophilic aromatic substitution with ferrocene to form a ferrocenylphosphirene complex. Chloride abstraction from 2 with silver triflate leads to a phosphirenyl triflate complex, which reacts with PPh3 and ferrocene in the same fashion as 3 but also reacts cleanly with a wider range of substrates, including phenylacetylene and allyltrimethylsilane, to form respectively a phenylalkynylphosphirene complex and an allylphosphirene complex.

Recent advances in manganese(iii) acetate mediated organic synthesis

The preceding four decades have witnessed a major expansion in the field of free-radical assisted reactions, as they are becoming a key tool in organic, polymer and complex natural product chemistry. This progress has clearly changed the traditional idea of free-radical reactions being “extremely uncontrollable”, thereby allowing chemists to deal with free radicals in a more accurate and controlled way. Manganese(III) acetate mediated radical reactions have reached distinction in this field, as a wide range of protocols involving manganese(III) acetate under mild and efficient reaction conditions have been developed for the synthesis of biologically active and important organic molecules through oxidation, addition and cyclization reactions, which are in general difficult to achieve by the established synthetic operations. The present review focuses on manganese(III) acetate mediated oxidative free-radical reactions that have been developed and adapted during the last five years. It includes the advancements made in the field of free-radical promoted carbon–carbon and carbon–oxygen bond forming reactions, illustrating the examples of furans, hydrofurans, pyrroles, bicyclic lactones, biaryls, oxepins, indole-alkaloids, 1,2-benzanthracene and C60-fused tetrahydronaphthalene synthesis. Numerous manganese(III) acetate initiated carbon–phosphorus bond formation reactions were also devised during recent years, involving both phosphonyl and phosphinoyl radicals, and are a key part of this review. Manganese(III) acetate promotes functionalization of significant organic compounds, thereby guiding the synthesis of important and complex molecules, such as the formation of propellanes, quinolinones, 1,2-dioxalanes; oxidation of indoles; lactonization of fullerene [C60], malonyl cyclopentanes, glycols; and hydroperoxidation of heterocycles. The review will also envelop several recent milestones that have been achieved in the chemistry of natural products precising the vital role of manganese(III) acetate in the key synthetic steps.

Reaction of P,P,P-trihalogenbenzo-1,3,2-dioxaphospholes with terminal acetylenes: Phosphorus-carbon bond formation and the ipso-substitution of oxygen by carbon

The account covers a new reaction in phosphorus chemistry, namely, the interaction of 2,2,2-trihalobenzo-1,3,2-dioxaphospholes with aryl(alkyl)acetylenes, which leads to the formation of benzo[e]-1,2-oxaphosphinine derivatives, or “phosphacoumarins.” The easy formation of a P-C bond and phosphoryl group, the ipso-substitution of the oxygen atom by the carbon one, and selective chlorination para to endocyclic oxygen are realized under mild conditions in this reaction. The ipso-substitution of a tertiary butyl group and a bromine atom also takes place in some cases.

ChemInform Abstract: Phosphorus—Carbon Bond Formation by Using a Silylphosphine as a Phosphorus Source

AbstractReview: 25 refs.

シリルホスフィンを利用するリン‐炭素結合生成反応

Organophosphines play an important role in the field of organic synthesis, especially as ligands in transition metal catalysis. However, the synthesis of organophosphines with various functional groups still has many difficulties due to limitations in phosphorus-carbon bond formation. In this review, recent advances in the syntheses of organophosphines having various functional groups by using silylphosphines under mild conditions are described. Sterically protected silylphosphines are effectively applied to selective formations of several types of carbon-phosphorus bond, via three types of adequate activations; activation of a phosphorus-silicon bond of a silylphosphine by means of a fluoride, nucleophilic attack to the electrophile activated by a Lewis acid, and a transition-metal catalyzed activation of phosphorus-silicon bond. One successful application of a stepwise functional phosphine synthesis is also described.

Reactivity of the triruthenium ortho-metalated cluster [Ru 3(CO) 9{μ 3-η 1,κ 1,κ 2-PhP(C 6H 4)CH 2PPh}] with tri(2-thienyl)phosphine and tri(2-furyl)phosphine: Formation of 1,3-diphenyl-2,3-dihydro-1H-1,3-benzodiphosphine complexes via phosphorus–carbon bond formation

Reaction of [Ru 3(CO) 9{μ 3-η 1,κ 1,κ 2-PhP(C 6H 4)CH 2PPh}] ( 1) with tri(2-thienyl)phosphine (PTh 3) in refluxing THF afforded [Ru 3(CO) 9(PTh 3)(μ-dpbm)] ( 3) {dpbm = PhP(C 6H 4)(CH 2)PPh} and [Ru 3(CO) 6(μ-CO) 2{μ-κ 1,η 1-PTh 2(C 4H 2S)}{μ 3-κ 1,κ 2-Ph 2PCH 2PPh}] ( 5) in 18% and 12% yields, respectively, while a similar reaction with tri(2-furyl)phosphine (PFu 3) gave [Ru 3(CO) 9(PFu 3)(μ-dpbm)] ( 4) and [Ru 3(CO) 7(μ-η 1,η 2-C 4H 3O)(μ-PFu 2){μ 3-η 1,κ 1,κ 2-PhP(C 6H 4)CH 2PPh}] ( 6) in 24% and 27% yields, respectively. Compounds 2 and 4 are phosphine adducts of 1 in which the diphosphine ligand is transformed into 1,3-diphenyl-2,3-dihydro-1H-1,3-benzodiphosphine (dpbm) via phosphorus–carbon bond formation. Cluster 5 results from metalation of a thienyl ring, the cleaved proton being transferred to the diphosphine. Carbon–phosphorus bond cleavage of a PFu 3 ligand is observed in 6 to afford a phosphido-bridge and a furyl fragment, the latter bridging in a σ,π-vinyl fashion. The molecular structures of 3, 5 and 6 have been determined by X-ray diffraction studies.

ChemInform Abstract: Carbon—Phosphorus Bond Formation and Transformation in the Reaction of 1,2‐Diaza‐1,3‐butadienes with Alkyl Phenylphosphonites.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Recent Developments in the Addition of Phosphinylidene‐Containing Compounds to Unactivated Unsaturated Hydrocarbons: Phosphorus—Carbon Bond Formation by Hydrophosphinylation and Related Processes.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Recent Developments in the Addition of Phosphinylidene-Containing Compounds to Unactivated Unsaturated Hydrocarbons: Phosphorus-Carbon Bond-Formation via Hydrophosphinylation and Related Processes.

The reactions of phosphinylidene-containing compounds with unactivated unsaturated hydrocarbons are reviewed. The review is organized by phosphorus-containing functional group types. Free-radical and metal-catalyzed additions of R(1)R(2)P(O)H to alkenes, alkynes, and related compounds, deliver functionalized organophosphorus compounds RP(O)R(1)R(2), including H-phosphinates, phosphinates, tertiary phosphine oxides, and phosphonates. The review covers the literature up to February 2008.

Carbon–phosphorus bond formation and transformation in the reaction of 1,2-diaza-1,3-butadienes with alkyl phenylphosphonites

The reaction of 1,2-diaza-1,3-butadienes with dialkyl phenylphosphonites under solvent-free conditions proceeds via zwitterionic intermediate and gives, by precipitation, the stable ylidic α-phosphanylidene-hydrazones that, in turn, can be transformed into the corresponding 3-phenyl-2 H-1,2,3λ 5-diazaphospholes. The latter compounds are converted by hydrolytic cleavage in methanol–water (95:5) into E-hydrazonophosphonates that are useful for the preparation of the corresponding β-ketophosphonates and 4-[alkoxy(phenyl)phosphoryl]-1,2-diaza-1,3-butadienes. These peculiar 1,2-diaza-1,3-butadienes, bearing an alkoxy(phenyl)phosphoryl group on the carbon atom in position 4 are also able to add different nucleophiles, such as methanol or thiourea, giving 2-[alkoxy(phenyl)phosphoryl]-2-methoxyhydrazones and 5-phosphinate-substituted thiazol-4-ones, respectively.

ChemInform Abstract: Phosphorus—Carbon Bond Formation by Lewis Acid Catalyzed/Mediated Addition of Silylphosphines.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Metal-Catalyzed Asymmetric Synthesis of P-Stereogenic Phosphines

This account summarizes our attempts to develop metal-catalyzed asymmetric syntheses of P-stereogenic phosphines. While such phosphines undergo pyramidal inversion slowly at room temperature, inversion is rapid in metal-phosphido com­plexes (M-PR2). These observations were the basis for catalytic, dynamic kinetic resolution processes in which racemic secondary phosphines [PR(R′)H] were converted into enantioenriched tertiary phosphines [PR(R′)(R′′)] by platinum-catalyzed asymmetric hydrophosphination of acrylonitrile or related Michael acceptors, by ­palladium-catalyzed asymmetric phosphination of aryl iodides using secondary phosphines or phosphine-boranes, and by platinum-catalyzed asymmetric alkylation of secondary phosphines. The key intermediates were diastereomeric phosphido complexes with chiral ancillary ligands (Ln*-M-PRR′). Their relative rates of P-inversion and phosphorus-carbon bond formation controlled the enantioselectivity of product formation, whether the phosphorus-carbon bonds were formed by reductive elimination (for Pd), or by the reaction of a platinum-phosphido complex with an electrophile (an alkene in hydrophosphination, or a benzyl bromide in alkylation). The results of mechanistic studies and their use in the design of improved catalytic reactions are described.

A novel approach to phosphonic acids from hypophosphorous acid

A novel access to phosphonic acids via Pd-catalyzed tandem carbon–phosphorus bond formation–oxidation processes was developed. The procedures involve atom-economical and environmentally friendly functionalization reactions of hypophosphorous acid (H3PO2) and H-phosphinic acids [RP(O)(OH)(H)].

Phosphorus—Carbon Bond Formation Catalyzed by Electrophilic N‐Heterocyclic Phosphines.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

The other half of the Michaelis–Arbuzov reaction: A new synthetic route to tertiary phosphorus–carbon bond formation

A first-row transition metal assisted modification of the Michaelis–Arbuzov rearrangement has been discovered that allows the reaction to take place under ambient conditions using a mild phosphine nucleophile. This reaction has been used as a novel synthetic strategy for the assembly of P–C bonds in typically difficult to construct 3-methylpyridyl substituted phosphine and phosphonium ligands. Metal complexes of these ligands were characterized crystallographically. One of the products also contains the previously unknown pyridylFeCl 3 - species.

Synthesis of Enantiopure 1‐r‐Aryl‐2‐c,5‐t‐diphenylphospholane Oxides and Boranes by Pd‐Catalyzed C–P Bond Formation

AbstractNew chiral enantiopure phospholane oxides 1 and boranes 5 were obtained from efficient carbon–phosphorus bond formation by organocuprate or palladium‐catalyzed reactions. C–P cross‐coupling reactions between chiral phosphane oxide 3 or borane 4 and various aryl derivatives are presented.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Phosphorus–carbon bond formation catalysed by electrophilic N-heterocyclic phosphines

A P-chloro-diazaphospholene catalyses the phosphorus-carbon bond formation reaction between diphenylsilylphosphine and various alkyl chlorides.