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The Wittig reaction is renowned as exceptionally versatile method for converting a diversity of aldehydes and ketones into alkenes. Recently, strategies for chiral phosphine catalysis under PIII/PV=O redox cycling emerged to render this venerable transformation stereoselective. Herein, we describe that phosphine redox catalysis enables the enantioselective synthesis of pertinent biaryl atropisomers by means of a stereocontrolled arene‐forming Wittig reaction. Key to the process is the release of an endogenous base from readily accessible tert‐butyloxycarbonylated Morita–Baylis–Hillman adducts triggered by catalyst intramolecularization, permitting mild phosphine redox catalysis for atroposelective Wittig reactions. By this strategy, a broad diversity of biaryl atropisomers is obtained with up to 94 : 6 enantioselectivity. [ABSTRACT FROM AUTHOR]

The formation of phosphorus‐rich alanes featuring butterfly‐like geometries is achieved. The two‐electron reduction products feature a unique P42− structure and can act as a source of P3−. The treatment of these phosphorus containing products with electrophiles under mild conditions results in the formation of different phosphines. This approach eliminates the need for high temperatures and/or high pressures, which are commonly required in industrial processes for the preparation of useful phosphines.The activation and further functionalization of white phosphorus (P4) by main group complexes has become an increasingly studied topic in recent times. Herein, we report the controlled formation of phosphorus‐rich alanes featuring butterfly‐like geometries from the selective reaction of P4 with dialumenes, ([L(IiPr)Al]2) (1: L=Tripp=2,4,6‐iPr3C6H2; 2: L=tBu2MeSi; IiPr=[MeCN(iPr)]2C)). The two‐electron‐reduction product of P4 features a P42− structure and is shown to be able to act as a source of P3−. Treatments of different electrophiles (e.g. chlorotrimethylsilane (Me3SiCl), iodotrimethylsilane (Me3SiI), HCl, or acetyl chloride (CH3COCl)) with these alanes under mild conditions gave the corresponding phosphines (e.g. P(SiMe3)3, PH3, or P(COCH3)3). [ABSTRACT FROM AUTHOR]

Since the discovery of the palladium/norbornene (Pd/NBE)‐catalyzed ortho amination in 2013, escaping the limitation of only yielding tertiary anilines has been a long‐standing challenge. Here, we describe that, by carefully choosing the phosphine ligand and NBE mediator, the installation of a N‐mono‐alkylamino group becomes feasible. The reaction tolerates a wide range of aryl iodide substrates and various N‐mono‐tertiary alkylamine‐derived electrophiles. Both ipso alkenylation and alkynylation can be realized. The synthetic utility of this method is exemplified by the formation of primary amino group via selective deprotection and streamlined access to N‐heterocycles. Preliminary success of installing a bulky N‐secondary alkylamino group and a mechanistic understanding of the decomposition pathways of mono N‐alkylamine electrophiles have been obtained. [ABSTRACT FROM AUTHOR]

Phosphine‐functionalized metal‐organic frameworks (P‐MOFs) as an emerging class of coordination polymers, have provided novel opportunities for the development of heterogeneous catalysts. Yet, compared with the ubiquitous phosphine systems in homogeneous catalysis, heterogenization of phosphines in MOFs is still at its early stage. In this Minireview, we summarize the synthetic strategies, characterization and catalytic reactions based on the P‐MOFs reported in literature. In particular, various catalytic reactions are discussed in detail in terms of phosphine ligand structure‐function relationship, including the potential obstacles for future development. Finally, we discuss the possible solutions, including new types of reactions and techniques as the perspectives for the development of P‐MOF catalysts, highlighting the opportunities and challenges. [ABSTRACT FROM AUTHOR]

Atropisomeric phosphines hold considerable significance in asymmetric catalysis, yet their synthesis presents a formidable challenge owing to intricate multistep procedures. In this context, a groundbreaking methodology has been presented for their preparation. This innovative approach entails an atroposelective rhodium‐catalyzed C−H activation employing aryl and heteroaryl halides, chelated by a P(III) center. The essence of this strategy lies in its ability to directly construct chiral phosphine ligands in a single step, thereby exhibiting exceptional efficiency in terms of atom and redox economy. Illustrative examples serve to demonstrate the immense potential of in situ‐formed ligands in asymmetric catalysis. Mechanistic experiments have further provided invaluable insights into this transformation. [ABSTRACT FROM AUTHOR]

A new phosphine‐catalyzed reaction of α‐substituted allenes with aryl imines, in stark contrast to classic cycloaddition reactions, has been developed. This reaction delivers valuable highly functionalized itaconimides with excellent stereoselectivities by a new «un‐cyclizing» reaction mode involving β′‐carbon of α‐substituted allenes. Moreover, the present «un‐cyclizing» reaction can also be carried out in a one‐pot fashion and scaled up to the gram scale by using aryl aldehydes, without the need to isolate the aryl imines. Mechanistic studies and control experiments reveal the crucial role of H2CO3 for the present reaction mode. In addition, density functional theory (DFT) calculations were performed to understand the possible mechanism. [ABSTRACT FROM AUTHOR]

Metal‐catalyzed C−H activation strategies provide an efficient approach for synthesis by minimizing atom, step, and redox economy. Developing milder, greener, and more effective protocols for these strategies is always highly desirable to the scientific community. In this study, the utilization of a single rhodium complex enabled the visible‐light‐induced late‐stage C−H activation of biaryl‐type phosphines with alkynyl bromides, employing inherent phosphorus atoms as directing groups. This chemistry combines P(III)‐directed C−H activation with visible light photocatalysis, under exogenous photosensitizer‐free conditions, offering a unique platform for ligand design and preparation. Furthermore, this study also explores the asymmetric catalysis and coordination chemistry of the resulting P‐alkyne hybrid ligands with specific transition metals. Experimental results and density functional theory calculations demonstrate the mechanistic intricacies of this transformation. [ABSTRACT FROM AUTHOR]

Catalytic asymmetric methods for the synthesis of synthetically versatile P‐stereogenic building blocks offer an efficient and practical approach for the diversity‐oriented preparation of P‐chiral phosphorus compounds. Herein, we report the first nickel‐catalyzed synthesis of P‐stereogenic secondary aminophosphine‐boranes by the asymmetric addition of primary phosphines to azo compounds. We further demonstrate that the P−H and P−N bonds on these phosphanyl hydrazine building blocks can be reacted sequentially and stereospecifically to access various P‐stereogenic compounds with structural diversity. [ABSTRACT FROM AUTHOR]

The phosphino‐phosphonium cations of the form [R3PPR′2]+ are labile and provide access to the constituent Lewis acidic and Lewis basic fragments. This permits frustrated Lewis pair‐type addition reactions to alkynes, affording unprecedented phosphino‐phosphination reactions and giving cations of the form [cis‐R3PCHC(R′′)PR′2]+. This reactivity is further adapted to prepare several examples of a rare class of dissymmetric cis‐olefin‐linked bidentate phosphines. [ABSTRACT FROM AUTHOR]

Pnictogen bonding (PnB) has gained recognition as an appealing strategy for constructing novel architectures and unlocking new properties. Within the synthetic community, the development of a straightforward and much simpler protocol for cross‐electrophile C−PIII coupling remains an ongoing challenge with organic halides. In this study, we present a simple strategy for photoinduced PnB‐enabled cross‐electrophile C−PIII couplings using readily available chlorophosphines and organic halides via merging single electron transfer (SET) and halogen atom transfer (XAT) processes. In this photomediated transformation, the PnB formed between chlorophosphines and alkyl amines facilitates the photogeneration of PIII radicals and α‐aminoalkyl radicals through SET. Subsequently, the resulting α‐aminoalkyl radicals activate C−X bonds via XAT, leading to the formation of carbon radicals. This methodology offers operational simplicity and compatibility with both aliphatic and aromatic chlorophosphines and organic halides. [ABSTRACT FROM AUTHOR]

Herein, we describe the feasibility of atroposelective PIII/PV=O redox organocatalysis by the Staudinger–aza‐Wittig reaction. The formation of isoquinoline heterocycles thereby enables the synthesis of a broad range of valuable atropisomers under mild conditions with enantioselectivities of up to 98 : 2 e.r. Readily prepared azido cinnamate substrates convert in high yield with stereocontrol by a chiral phosphine catalyst, which is regenerated using a silane reductant under Brønsted acid co‐catalysis. The reaction provides access to diversified aryl isoquinolines, as well as benzoisoquinoline and naphthyridine atropisomers. The products are expeditiously transformed into N‐oxides, naphthol and triaryl phosphine variants of prevalent catalysts and ligands. With dinitrogen release and aromatization as ideal driving forces, it is anticipated that atroposelective redox organocatalysis provides access to a multitude of aromatic heterocycles with precise control over their configuration. [ABSTRACT FROM AUTHOR]

The selective transition‐metal catalyzed C−F bond functionalization of inexpensive industrial fluorochemicals represents one of the most attractive approaches to valuable fluorinated compounds. However, the selective C(sp2)−F bond carbofunctionalization of refrigerant hydrofluoroolefins (HFOs) remains challenging. Here, we report a nickel‐catalyzed selective C(sp2)−F bond alkylation of HFO‐1234yf with alkylzinc reagents. The resulting 2‐trifluoromethylalkenes can serve as a versatile synthon for diversified transformations, including the anti‐Markovnikov type hydroalkylation and the synthesis of bioactive molecule analogues. Mechanistic studies reveal that lithium salt is essential to promote the oxidative addition of Ni0(Ln) to the C−F bond; the less electron‐rich N‐based ligands, such as bipyridine and pyridine‐oxazoline, feature comparable or even higher oxidative addition rates than the electron‐rich phosphine ligands; the strong σ‐donating phosphine ligands, such as PMe3, are detrimental to transmetallation, but the less electron‐rich and bulky N‐based ligands, such as pyridine‐oxazoline, facilitate transmetallation and reductive elimination to form the final product. [ABSTRACT FROM AUTHOR]

We describe a copper catalyst that promotes the addition of phosphines to cyclopropenes at ambient temperature. A range of cyclopropylphosphines bearing different steric and electronic properties can now be accessed in high yields and enantioselectivities. Enrichment of phosphorus stereocenters is also demonstrated via a Dynamic Kinetic Asymmetric Transformation (DyKAT) process. A combined experimental and theoretical mechanistic study supports an elementary step featuring insertion of a CuI‐phosphido into a carbon‐carbon double bond. Density functional theory calculations reveal migratory insertion as the rate‐ and stereo‐determining step, followed by a syn‐protodemetalation. [ABSTRACT FROM AUTHOR]

The asymmetric hydrophosphination of cyclopropenes with phosphines is of much interest and importance, but has remained hardly explored to date probably because of the lack of suitable catalysts. We report here the diastereo‐ and enantioselective hydrophosphination of 3,3‐disubstituted cyclopropenes with phosphines by a chiral lanthanocene catalyst bearing the C2‐symmetric 5,6‐dioxy‐4,7‐trans‐dialkyl‐substituted tetrahydroindenyl ligands. This protocol offers a selective and efficient route for the synthesis of a new family of chiral phosphinocyclopropane derivatives, featuring 100 % atom efficiency, good diastereo‐ and enantioselectivity, broad substrate scope, and no need for a directing group. [ABSTRACT FROM AUTHOR]

Polyalkyl furans are widespread in nature, often performing important biological roles. Despite a plethora of methods for the synthesis of tetrasubstituted furans, the construction of tetraalkyl furans remains non-trivial. The prevalence of alkyl groups in bioactive furan natural products, combined with the desirable bioactivities of tetraalkyl furans, calls for a general synthetic protocol for polyalkyl furans. This paper describes a Michael-Heck approach, using sequential phosphine-palladium catalysis, for the preparation of various polyalkyl furans from readily available precursors. The versatility of this method is illustrated by the total syntheses of nine distinct polyalkylated furan natural products belonging to different classes, namely the furanoterpenes rosefuran, sesquirosefuran, and mikanifuran; the marine natural products plakorsins A, B, and D and plakorsin D methyl ester; and the furan fatty acids 3D5 and hydromumiamicin.

Photoinduced metal–organic framework (MOF) enabled heterogeneous thiol catalysis has been achieved for the first time. MOF Zr‐TPDCS‐1, consisting of Zr6‐clusters and TPDCS linkers (TPDCS=3,3′′,5,5′′‐tetramercapto[1,1′:4′,1′′‐terphenyl]‐4,4′′‐dicarboxylate), effectively catalyzed the borylation, silylation, phosphorylation, and thiolation of organic molecules. Upon irradiation, the fast electron transfer from TPDCS to Zr6‐cluster is believed to facilitate the formation of the thiyl radical, a hydrogen atom transfer catalyst, which competently abstracts the hydrogen from borane, silane, phosphine, or thiol for generating the corresponding element radical to engender the chemical transformations. The elaborate control experiments evidenced the generation of thiyl radicals in MOF and illustrated a radical reaction pathway. The gram‐scale reaction worked well, and the product was conveniently separated via centrifugation and vacuum with a turnover number (TON) of ≈3880, highlighting the practical application potential of heterogeneous thiyl‐radical catalysis. [ABSTRACT FROM AUTHOR]

[1.1.1]Propellane, which is structurally simple and compact, exhibits promising potential for the synthesis of disubstituted straight‐shaped bicyclo[1.1.1]pentane (BCP) compounds by manipulation of its highly reactive internal C−C bond. BCPs are considered to be isosteres of 1,4‐disubstituted benzenes, which have found broad applications in the areas of functional molecules and drug discovery. The internal C−C single bond of [1.1.1]propellane is regarded as a charge‐shift bond, which can be readily cleaved by radical means to construct BCPs. We herein report a novel synthetic method for (un)symmetric diphosphines based on the BCP motif, which can be interpreted as isosteres of 1,4‐bis(diphenylphosphino)benzenes. The obtained BCP‐diphosphine derivatives were used to generate a straight‐shaped Au complex and an Eu‐based coordination polymer. [ABSTRACT FROM AUTHOR]

This invited Team Profile was created by the Gessner and Gooßen research groups at Ruhr‐University Bochum (Germany). They recently published a series of articles in Angewandte Chemie on the application of ylide‐substituted phosphines (YPhos) in palladium‐catalyzed coupling reactions. Owing to their inherently strong sigma‐donating ability and their modular synthesis, YPhos ligands can be tailored to fit the demands of various catalytic transformations. In the most recent article, machine learning methods were applied to identify a YPhos catalyst that enables the previously elusive Hiyama coupling of aryl chlorides. "Computer‐Driven Development of Ylide Functionalized Phosphines for Palladium‐Catalyzed Hiyama Couplings", J. F. Goebel, J. Löffler, Z. Zeng, J. Handelmann, A. Hermann, I. Rodstein, T. Gensch, V. H. Gessner, L. J. Gooßen, Angew. Chem. Int. Ed. 2023, e202216160; Angew. Chem. 2023, e202216160. [ABSTRACT FROM AUTHOR]

Catalytic enantioselective coupling of 1,1‐disubstituted allenes and aldehydes through regiodivergent oxidative cyclization followed by stereoselective protonation or reductive elimination promoted by chiral phosphine‐Co complexes is presented. Such processes represent unprecedented and unique reaction pathways for Co catalysis that enable catalytic enantioselective generation of metallacycles with divergent regioselectivity accurately controlled by chiral ligands, affording a wide range of allylic alcohols and homoallylic alcohols that are otherwise difficult to access without the need of pre‐formation of stoichiometric amounts of alkenyl‐ and allyl‐metal reagents in up to 92 % yield, >98 : 2 regioselectivity, >98 : 2 dr and >99.5 : 0.5 er. [ABSTRACT FROM AUTHOR]

A chiral Brønsted acid‐catalysed asymmetric hydrophosphinylation of 2‐vinylazaarenes by secondary phosphine oxides is described. A variety of P‐chiral 2‐azaaryl‐ethylphosphine oxides are synthesized with high yields and ees, of which both the substituents of phosphines and azaarenes can be flexibly modulated, underscoring an exceptionally broad scope of substrates. These adducts are valuable to asymmetric metal catalysis since the resultant P‐chiral tertiary phosphines from the reduction of them are verified as a kind of effective C1‐symmetric chiral 1,5‐hybrid P,N‐ligands. Importantly, this catalysis platform enables the generic and efficient kinetic resolution of P‐chiral secondary phosphine oxides. It thus provides an expedient approach to access the enantiomers of the P‐chiral tertiary phosphine oxides derived from asymmetric hydrophosphinylation, further improving the utility of the method. [ABSTRACT FROM AUTHOR]

Pd‐catalyzed nucleophilic fluorination reactions are important methods for the synthesis of fluoroarenes and fluoroalkenes. However, these reactions can generate a mixture of regioisomeric products that are often difficult to separate. While investigating the Pd‐catalyzed fluorination of cyclic vinyl triflates, we observed that the addition of a substoichiometric quantity of TESCF3 significantly improved the regioselectivity of the reaction. Herein, we report a combined experimental and computational study on the mechanism of this transformation focusing on the role of TESCF3. The poor regioselectivity of the reaction in the absence of additives results from the formation of LPd‐cyclohexyne complexes (L=biaryl monophosphine ligand). When TESCF3 is added to the reaction mixture, the generation of the Pd‐cyclohexyne complexes is diminished by an unexpected pathway involving the dearomatization of the ligand by nucleophilic attack from a trifluoromethyl anion (CF3−). [ABSTRACT FROM AUTHOR]

The simplest diphosphene HPPH and isomeric diphosphinyldene PPH2 features prototype phosphorus‐phosphorus multiple bonding properties that have been of long‐standing interest in main‐group chemistry. Herein, we report the observation of cis‐HPPH, trans‐HPPH, and PPH2 among the respective laser photolysis products of phosphine (PH3) and diphosphine (P2H4) in solid N2‐ and Ar‐matrices at 10 K. The identification of these P2H2 isomers with matrix‐isolation IR and UV/Vis spectroscopy is supported by D‐isotope labeling and the quantum chemical calculations at the CCSD(T)‐F12a/cc‐pVTZ‐F12 level using configuration‐selective vibrational configuration interaction theory (VCI). Bonding analyses suggest that the two conformers of HPPH contain standard PP double bonds, whereas, PPH2 resembles P2 in having partial PP triple bond due to the H2P←P π bonding interaction. [ABSTRACT FROM AUTHOR]

The simplest diphosphene HPPH and isomeric diphosphinyldene PPH2 features prototype phosphorus‐phosphorus multiple bonding properties that have been of long‐standing interest in main‐group chemistry. Herein, we report the observation of cis‐HPPH, trans‐HPPH, and PPH2 among the respective laser photolysis products of phosphine (PH3) and diphosphine (P2H4) in solid N2‐ and Ar‐matrices at 10 K. The identification of these P2H2 isomers with matrix‐isolation IR and UV/Vis spectroscopy is supported by D‐isotope labeling and the quantum chemical calculations at the CCSD(T)‐F12a/cc‐pVTZ‐F12 level using configuration‐selective vibrational configuration interaction theory (VCI). Bonding analyses suggest that the two conformers of HPPH contain standard PP double bonds, whereas, PPH2 resembles P2 in having partial PP triple bond due to the H2P←P π bonding interaction. [ABSTRACT FROM AUTHOR]

Hemilabile ligands have been applied extensively in transition metal catalysis, but preparations of these molecules typically require multistep synthesis. Here, modular assembly of diverse phosphine‐amide ligands, including related axially chiral compounds, is first reported through ruthenium‐catalyzed C−H activation of phosphines with isocyanate directed by phosphorus(III) atoms. High reactivity and regioselectivity can be obtained by using a Ru3(CO)12 catalyst with a mono‐N‐protected amino acid ligand. This transformation significantly expands the pool of phosphine‐amide ligands, some of which have shown excellent efficiency for asymmetric catalysis. More broadly, the discovery constitutes a proof of principle for facile construction of hemilabile ligands directly from the parent monodentate phosphines by C−H activation with ideal atom, step and redox economy. Several dinuclear ruthenium complexes were characterized by single‐crystal X‐ray diffraction analysis revealing the key mechanistic features of this transformation. [ABSTRACT FROM AUTHOR]

A chiral Brønsted acid catalysed phosphine‐mediated deoxygenation protocol is reported. This metal‐free method provides a precise kinetic resolution platform for azaarylethynyl tertiary alcohols, which are a broad category of biologically and synthetically important azaarene derivatives. In addition to providing an efficient method for the first asymmetric preparation of these tertiary alcohols, the strategy facilitates the construction of azaaryl‐functionalized allenes with good to excellent enantioselectivities. The high selectivity factors (s up to 235), broad substrate scope, and ability to convert azaaryl compounds into both chiral tertiary alcohols and allenes robustly underscore the efficiency and promising utility of this method. The practicability is further validated by the successful synthesis of deuterated allenes with high ee values and substantial incorporation of deuterium using inexpensive D2O as the deuterium source. [ABSTRACT FROM AUTHOR]

An iridium‐catalyzed asymmetric synthesis of branched allylic phosphine compounds under mild conditions is reported. Products bearing various functional groups can be synthesized with excellent stereoselectivity (up to 99.9 % ee) and regioselectivity. The employment of phosphine sulfides with relatively low deactivation capacity against metal catalysts is crucial for the success of this reaction. [ABSTRACT FROM AUTHOR]

The first copper‐catalyzed regiodivergent cyanoboration of internal allenes with B2pin2 (bis(pinacolato)diboron) and NCTS (N‐cyano‐N‐phenyl‐p‐toluenesulfonamide) derivatives is reported. The β,γ‐ and α,β‐cyanoborylated products were synthesized with high regio‐ and stereo‐selectivity. Computational studies revealed that nucleophilic addition of allylcopper or related intermediates on cyanation reagent is the regio‐ and stereo‐determining step, while transmetalation with B2pin2 is the rate‐determining step. The nucleophilic addition step proceeds via inner‐sphere mechanism in the CuI/P(o‐tol)3 and CuI/Xantphos (P(o‐tol)3=tris(o‐methylphenyl)phosphine, Xantphos=4,5‐bis(diphenylphosphino)‐9,9‐dimethylxanthene) catalytic systems and via outer‐sphere mechanism in the CuII/Xantphos catalytic system, respectively. [ABSTRACT FROM AUTHOR]

A photochemically induced selective and divergent cyanation reaction of alkynes, enabled by phosphorus radicals, is described. With the use of simple triarylphosphine as a co‐catalyst, three cyanation reactions, including di‐hydrocyanation, anti‐Markovnikov hydrocyanation, and domino hydrocyanation/reduction, can be divergently achieved, furnishing a wide array of alkyl dinitriles, alkenyl nitriles, and alkyl nitriles under mild conditions. Terminal and internal alkynes are applicable with high efficiency and excellent selectivity. Synthetic applications for biologically active agents and preliminary experimental and computational mechanistic studies are reported. [ABSTRACT FROM AUTHOR]

A ligand‐controlled rhodium‐catalyzed regiodivergent arylation of alkenylthianthrenium salts with arylboroxines which allows the synthesis of terminal and internal alkene products in a switchable manner is reported. The use of a diene ligand guides the reaction toward cine‐arylation affording terminal alkenes, while the use of a phosphine ligand switches the reaction to ipso‐arylation exclusively giving internal alkenes. Deuterium labelling studies and DFT computations were carried out to investigate the mechanism. [ABSTRACT FROM AUTHOR]

The transition‐metal‐catalyzed C−P bond cleavage has emerged as a powerful tool for the formation of both C−C and C−P bond. However, the transition‐metal‐catalyzed stereoselective cleavage of C−P bond is still undeveloped. Herein, we report a palladium‐catalyzed stereoselective cleavage of C−P bond for the construction of P‐stereogenic phosphines and stereogenic axis. This protocol enables the quick synthesis of atropisomers bearing a P‐stereogenic center in high yields, diastereo‐ and enantioselectivities of up to 98 % ee, >25 : 1 dr. The product is able to serve as chiral catalyst in phosphine catalyzed [3+2] cycloaddition of allenoates to imines, showing the great potential of the present methodology. [ABSTRACT FROM AUTHOR]

Fluorinated group 16 moieties are attractive building blocks in synthetic chemistry but only few synthetic methods are available to prepare them. Herein, we report a new oxidative fluorination reagent capable of stabilizing reactive fluorinated anions. It consists of an SF5− anion and a chemically inert phosphonium cation and is exceptionally thermally stable. Accordingly, it was used to generate the SeF5− and TeF5− anions from the elemental chalcogens and to prepare the unknown tetrafluoro(phenyl)‐λ5‐selenate PhSeF4− and ‐tellurate PhTeF4− from the corresponding diphenyl dichalcogenides. In addition, we show that further derivatization of [PhTeF4]− by oxidation to trans‐PhTeF4O− and subsequent alkylation gives access to a new class of trans‐(alkoxy)(phenyl)tetrafluoro‐λ6‐tellanes (trans‐PhTeF4OR), thus providing an approach to introduce the functional group into organic molecules. [ABSTRACT FROM AUTHOR]

Fluorinated group 16 moieties are attractive building blocks in synthetic chemistry but only few synthetic methods are available to prepare them. Herein, we report a new oxidative fluorination reagent capable of stabilizing reactive fluorinated anions. It consists of an SF5− anion and a chemically inert phosphonium cation and is exceptionally thermally stable. Accordingly, it was used to generate the SeF5− and TeF5− anions from the elemental chalcogens and to prepare the unknown tetrafluoro(phenyl)‐λ5‐selenate PhSeF4− and ‐tellurate PhTeF4− from the corresponding diphenyl dichalcogenides. In addition, we show that further derivatization of [PhTeF4]− by oxidation to trans‐PhTeF4O− and subsequent alkylation gives access to a new class of trans‐(alkoxy)(phenyl)tetrafluoro‐λ6‐tellanes (trans‐PhTeF4OR), thus providing an approach to introduce the functional group into organic molecules. [ABSTRACT FROM AUTHOR]

Herein, cobaloxime is used for the first time as a catalyst for the synthesis of phosphorylated heteroaromatics, which is an intriguing and versatile functional motif. With visible‐light irradiation, cobaloxime not only oxidizes phosphine oxides to form phosphorus radicals (P‐radicals) for a subsequent reaction with radical acceptor isocyanides or heteroaromatics, but also combines the radical intermediate with β‐H elimination, thereby producing phosphorylated heteroaromatics with only H2 or CH4 as byproduct. Phosphine oxides with dialkyl, alkylaryl, and diaryl substituents could be directly transformed into phosphorylated phenanthridines, benzothiazoles, isoquinolines, and common heteroaromatics. This catalytic system features extremely mild conditions, broad substrate scope and good to excellent yields. Scale‐up reaction and sunlight reaction show the great application potential in the green synthesis of important organophosphorus chemicals. [ABSTRACT FROM AUTHOR]

Herein, we report the development of new Co complexes that have cyclopropane‐based diphosphine ligands and can catalyze highly chemo‐, regio‐, and stereoselective hydroboration reactions of unsymmetrical internal alkynes. These reactions exhibited unusual regioselectivity: specifically, reactions of aryl alkyl internal alkynes showed excellent cis‐β‐addition selectivity, and reactions of dialkyl internal alkynes gave excellent cis‐α‐addition selectivity. Highly regioselective hydroboration of unsymmetrical dialkyl internal alkynes cannot be achieved by other known methods. The reactions described herein are highly synthetically useful, particularly for the stereoselective synthesis of trisubstituted alkenylborates and alkenes. Mechanistic studies indicate that a CoI−H species is a plausible active catalyst and the rigid structure of the cyclopropane skeleton of the ligands and the crowded reaction pocket were responsible for the unprecedented regioselectivity. [ABSTRACT FROM AUTHOR]

The insertion copolymerization of polar olefins and ethylene remains a significant challenge in part due to catalysts′ low activity and poor thermal stability. Herein we demonstrate a strategy toward addressing these obstacles through ligand design. Neutral nickel phosphine enolate catalysts with large phosphine substituents reaching the axial positions of Ni achieve activity of up to 7.7×103 kg mol−1 h−1 (efficiency >35×103 g copolymer/g Ni) at 110 °C, notable for ethylene/acrylate copolymerization. NMR analysis of resulting copolymers reveals highly linear microstructures with main‐chain ester functionality. Structure‐performance studies indicate a strong correlation between axial steric hindrance and catalyst performance. [ABSTRACT FROM AUTHOR]

Compared with heteroarenes, homogeneous asymmetric hydrogenation of all‐carbon aromatic rings is a longstanding challenge in organic synthesis due to the strong aromaticity and difficult enantioselective control. Herein, we report the rhodium/diphosphine‐catalyzed asymmetric hydrogenation of all‐carbon aromatic rings, affording a series of axially chiral cyclic compounds with high enantioselectivity through desymmetrization or kinetic resolution. In addition, the central‐chiral cyclic compounds were also obtained by asymmetric hydrogenation of phenanthrenes bearing a directing group. The key to success is the introduction of chiral diphosphine ligands with steric hindrance and strong electron‐donating properties. The axially chiral monophosphine ligands could be obtained by simple conversion of the hydrogenation products bearing the phosphine atom. [ABSTRACT FROM AUTHOR]

The first rhodium‐catalyzed highly chemo‐, regio‐ and enantioselective hydroformylation of cyclopropyl‐functionalized trisubstituted alkenes affording useful chiral cyclopropyl entities is reported. Compared to generally used diphosphine ligands for asymmetric catalysis, the modified hybrid phosphorus ligand, named (R,S)‐DTBM‐Yanphos, can convert a series of readily available cyclopropyl‐functionalized trisubstituted alkenes into high‐value chiral cyclopropyl‐functionalized aldehydes with high selectivities (81–98 % ee). Gram‐scale reactions (TON up to 1500) and follow‐up transformations to the corresponding alcohol, acid, esters and nitrile are also presented. Finally, a possible hydroformylation mechanism involving ring‐open‐hydroformylation pathways is proposed based on control and deuteroformylation reactions. [ABSTRACT FROM AUTHOR]

Although ylides are commonly used reagents in organic synthesis, the parent methylphosphine MePH2 only exists in its phosphine form in the condensed phase. Its ylide tautomer H3P+−CH2− is considerably higher in energy. Here, we report on the formation of bis(sulfonyl)methyl‐substituted phosphines of the type (RO2S)2C(H)−PR2, which form stable PH ylides under ambient conditions, amongst the first examples of an acyclic phosphine which only exists in its PH ylide form. Depending on the exact substitution pattern the phosphines form an equilibrium between the PH ylide and the phosphine form or exist as one of both extremes. These phosphines were found to be ideal starting systems for the facile formation of α‐carbanionic phosphines. The carbanion‐functionalization leads to a switch from electron‐poor to highly electron‐rich phosphines with strong donor abilities and high basicities. Thus, the phosphines readily react with different electrophiles exclusively at the phosphorus atom and not at the carbanionic center. Furthermore, the anionic nature of the phosphines allows the formation of zwitterionic complexes as demonstrated by the isolation of a gold(I) complex with a cationic metal center. The cationic gold center allows for catalytic activity in the hydroamination of alkyne without requiring a further activation step. [ABSTRACT FROM AUTHOR]

We report herein a facile and highly modular access to an intriguing class of free Au‐substituted phosphines (AuPhos), namely (LAu)nPR3−n (L=singlet carbene ligand; R=H, aryl, alkyl, silyl) (n=1–3). The Tolman electronic parameter (TEP) values coupled with theoretical investigations showcase that Au‐substitution can boost the electron‐releasing ability of AuPhos, thus leading to an electronically and sterically tunable, extremely electron‐rich phosphorus center. The high basicity of AuPhos is attributed to the d‐p lone pair π‐repulsion arising from interaction between Au substituents and the lone pair at P. A series of multi‐nuclear transition metal complexes (i.e. Rh, Ir, Pd, Au, W, Mn) ligated by AuPhos are readily prepared via a straightforward process. Preliminary catalytic results reveal the facilitation of Pd‐catalyzed C−N coupling reactions and Ir‐catalyzed decarbonylation reactions via AuPhos. This work provides insights for future development of electron‐rich ligands. [ABSTRACT FROM AUTHOR]

The confinement of a catalytic site is an efficient strategy to control a reaction and modulate its selectivity. In the present work, a new class of structurally simple and easily accessible bulky tri‐(ortho‐biaryl)phosphine ligands were accessed, and their gold(I) complexes synthesized. Their X‐ray diffraction analysis and the comparative evaluation of their VBur% and G steric parameters against a series of gold complexes commonly employed in catalysis demonstrated their confined nature. Despite their notable steric congestion, these complexes exhibited remarkable catalytic activities and unusual selectivities, both in nature and level, that make them unique in the field of synthetic homogeneous gold catalysis. [ABSTRACT FROM AUTHOR]

A phosphine‐catalyzed highly enantioselective and diastereoselective (up to 98 % ee and >20 : 1 dr) (3+2) annulation between vinylcyclopropanes and N‐tosylaldimines has been developed, which allows facile access to a range of highly functionalized chiral pyrrolidines. Notably, this method makes use of vinylcyclopropanes as a synthon for phosphine‐mediated asymmetric annulation reaction, which will offer new opportunities for potential applications of cyclopropanes substrates in phosphine‐catalyzed organic transformations. [ABSTRACT FROM AUTHOR]

A novel pH‐responsive molecular shuttle based on a [2]rotaxane with a phosphine ligand has been designed and synthesized. In the rhodium‐catalyzed hydrogenation of α,β‐dehydroamino acid esters and aryl enamides, ON/OFF‐switchable catalysis was accomplished with high ON/OFF ratios by adjusting the movements of the rotaxane wheels located at the catalyst terminals with acid/base. Mechanistic studies using NMR spectroscopy and quasi in situ X‐ray photoelectron spectroscopy revealed that RhIII‐hydride species are possibly formed in a H2 atmosphere when the catalyst is in the OFF state. During the reaction, a heterolytic activation of dihydrogen occurs by the interlocked rotaxane dibenzylamine and RhI catalytic center acting as a frustrated Lewis pair. Subsequent homolytic splitting of dihydrogen with the newly formed RhI‐hydride species generates RhIII‐hydride species. These findings show that a substrate‐selective hydrogenation can be achieved by using the OFF‐state catalyst. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) constructed with M0 nodes are attractive targets due to the reactivity of these low‐valent metals, but examples of these MOFs remain exceedingly rare. The rational design of three‐dimensional MOFs with Pd0 and Pt0 nodes using tetratopic phosphine ligands is reported. Five new MOFs have been synthesized by systematic variation of the phosphine ligands and metal precursors employed, and these represent the first examples of MOFs constructed using phosphine–metal bonds as the sole structural component. The MOFs display solid‐state luminescence, with emission maxima that are significantly red‐shifted compared to Pd(PPh3)4. In addition, a RhI low‐valent coordination solid based on the same linker design is reported, which displays solid‐state luminescence that is not observed for the molecular analogue. [ABSTRACT FROM AUTHOR]

While of interest, synthetically feasible access to boryl ligands and complexes remains limited, meaning such complexes remain underexploited in catalysis. For bidentate boryl ligands, oxidative addition of boranes to low‐valent IrI or Pt0 are the only examples yet reported. As part of our interest in developing improved group 10 ethylene polymerization catalysts, we present here an optimized synthesis of a novel, rigid borane/phosphine ligand and its Ni0 σ‐borane complex. From the latter, an unprecedented oxidative dehydrochloroborylation, to give a NiII boryl complex, was achieved. Furthermore, this new B/P ligand allowed the nickel‐catalyzed polymerization of ethylene, which suggests that Ni0 σ‐hydroborane complexes act as masked NiII boryl hydride reagents. [ABSTRACT FROM AUTHOR]

Phosphine‐mediated deoxygenative nucleophilic substitutions, such as the Mitsunobu reaction, are of great importance in organic synthesis. However, the conventional protocols require stoichiometric oxidants to trigger the formation of the oxyphosphonium intermediates for the subsequent nucleophilic additions. Through dual catalysis of photoredox and cobaloxime, we realized a radical strategy for the catalytic formation of acyloxyphosphonium ions that enables direct amidation. The deoxygenative protocol exhibits a broad scope and has been used in the late‐stage amidation of drug molecules. In addition to batch reactions, a continuous‐flow reactor was developed, enabling rapid peptide synthesis on gram scale. The successful assembly of a tetrapeptide on the solid support further demonstrated the versatility of this photocatalytic system. Moreover, experimental and computational studies are consistent with the hypothesis of acyloxyphosphonium ions being formed as the key intermediates. [ABSTRACT FROM AUTHOR]

Spectacular progress has recently been achieved in transition metal‐catalyzed C−H borylation of phosphines as well as directed electrophilic C−H borylation. As shown here, P‐directed electrophilic borylation provides a new, straightforward, and efficient access to phosphine–boranes. It operates under metal‐free conditions and leverages simple, readily available substrates. It is applicable to a broad range of backbones (naphthyl, biphenyl, N‐phenylpyrrole, binaphthyl, benzyl, naphthylmethyl) and gives facile access to various substitution patterns at boron (by varying the boron electrophile or post‐derivatizing the borane moiety). NMR monitoring supports the involvement of P‐stabilized borenium cations as key intermediates. DFT calculations reveal the existence and stabilizing effect of π‐arene/boron interactions in the (biphenyl)(i‐Pr)2P→BBr2+ species. [ABSTRACT FROM AUTHOR]

Disclosed herein is the first carbene‐organocatalyzed asymmetric addition of phosphine nucleophiles to the in situ generated α,β‐unsaturated acyl azolium intermediates. Our reaction enantioselectively constructs carbon–phosphine bonds and prepares chiral phosphines with high optical purities. The phosphine products are suitable for transforming to chiral ligands or catalysts with applications in asymmetric catalysis. The diarylalkyl or trialkyl phosphine products from our catalytic reactions, air‐sensitive and reactive in nature, can be trapped (and stored) in their sulfur‐oxidized form for operational simplicities. [ABSTRACT FROM AUTHOR]

Herein, we report a feasible molecular design of the binuclear clusters featuring the n‐p‐n heterojunction of biligand‐sandwiched inorganic units, which can be used as the effective charge trapper in ambipolar transistor memories with the large memory windows and the energy‐saving operation. We found that the hole confinement on the p‐type inorganic units is enhanced by spatial electronic anisotropy provided by the peripheral n‐type organic phosphine ligands. The steric hindrance of the coordination sites, the insulating effect of the carbon‐phosphorous single bonds and the parallel dual‐ligand coordination mode jointly elongate the interunit distances to nanometer scale and restrain the intramolecular electronic communications, leading to the tunable and reliable charge trapping. Our results show that the spatial effect is crucial to further amplifying the electronic differences between organic and inorganic units for function enhancement. [ABSTRACT FROM AUTHOR]

A geometrically constrained phosphine bearing a tridentate NNS pincer ligand is reported. The effect of the geometric constraint on the electronic structure was probed by theoretical calculations and derivatization reactions. Reactions with N−H bonds result in formation of cooperative addition products. The thermochemistry of these transformations is strongly dependent on the substrate, with ammonia activation being thermoneutral. This represents the first example of a molecular compound that reversibly activates ammonia via N−H bond scission in solution upon mild heating. [ABSTRACT FROM AUTHOR]

Secondary ligand–metal interactions are decisive in many catalytic transformations. While arene–gold interactions have repeatedly been reported as critical structural feature in many high‐performance gold catalysts, we herein report that these interactions can also be replaced by Au⋅⋅⋅H−C hydrogen bonds without suffering any reduction in catalytic performance. Systematic experimental and computational studies on a series of ylide‐substituted phosphines featuring either a PPh3 (PhYPhos) or PCy3 (CyYPhos) moiety showed that the arene‐gold interaction in the aryl‐substituted compounds is efficiently compensated by the formation of Au⋅⋅⋅H−C hydrogen bonds. The strongest interaction is found with the C−H moiety next to the onium center, which due to the polarization results in remarkably strong interactions with the shortest Au⋅⋅⋅H−C hydrogen bonds reported to date. Calorimetric studies on the formation of the gold complexes further confirmed that the PhYPhos and CyYPhos ligands form similarly stable complexes. Consequently, both ligands showed the same catalytic performance in the hydroamination, hydrophenoxylation and hydrocarboxylation of alkynes, thus demonstrating that Au⋅⋅⋅H−C hydrogen bonds are equally suited for the generation of highly effective gold catalysts than gold‐arene interactions. The generality of this observation was confirmed by a comparative study between a biaryl phosphine ligand and its cyclohexyl‐substituted derivative, which again showed identical catalytic performance. These observations clearly support Au⋅⋅⋅H−C hydrogen bonds as fundamental secondary interactions in gold catalysts, thus further increasing the number of design elements that can be used for future catalyst construction. [ABSTRACT FROM AUTHOR]