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Despite the appeal of organic redox systems as next-generation energy-storage media, achieving high cell voltages with electrolytes based on main-group elements typically comes at the cost of reduced long-term stabilities. In this Synpacts article, we summarize our recent finding that the introduction of phosphine oxide functionalities can unlock the ability of terthiophenes to serve as robust two-electron acceptors at extreme potentials. These investigations uncovered a fundamentally new class of multielectron redox systems, capable of expanding the cell potential range achievable with organic electrolytes without compromising stability. [ABSTRACT FROM AUTHOR]

A photooxidation approach to the conversion of phosphines into the corresponding phosphine oxides is reported. By taking advantage of O2 in the air as an oxidant and oxygen source, phosphine oxides were obtained efficiently in moderate to excellent yields. A four-coordinated organoboron compound was used as the photocatalyst to activate O2 to its singlet state. This photooxidation method features mild reaction conditions, broad functional-group tolerance, and a wide substrate scope. [ABSTRACT FROM AUTHOR]

This article discusses the synthesis of a new P-chiral phospholene core-based ligand called LemPhos. The authors propose a method using a chiral diene to create diastereomers that are easier to separate, allowing for the production of P-chiral ligands. The ligands are synthesized and characterized, and their application as catalysts in asymmetric hydrogenation reactions is explored. The document also includes experimental procedures and spectroscopic data for the synthesized compounds. The research is dedicated to the memory of Stanisław Lem, a renowned science-fiction writer. [Extracted from the article]

This article discusses a study on a new method for a visible-light-induced three-component radical coupling. The researchers tested the reaction of selenocarbonates and selenocarbamates and found that increasing the stability of the acyl radical facilitated the reaction. They also explored the reaction under thermal and photochemical conditions and provided detailed experimental data. The research has potential applications in natural-products synthesis and provides insights into the mechanism of the reaction and its potential applications in organic synthesis. [Extracted from the article]

This article provides an overview of photoredox-catalyzed C(sp2)–H bond functionalization reactions, which use low-energy photons to enable reactions under mild conditions. It discusses the contributions of researchers in advancing the field and explores the potential of using organic photocatalysts. The article focuses on the author's group's work in utilizing these reactions for C–H bond functionalizations, specifically in the context of enamides. The researchers explored various reactions, including the functionalization of enamide β-C(sp2)-H bonds, phosphorylation of alkenyl C(sp2)-H bonds, and bromination and alkylation of (hetero)arene C(sp2)-H bonds. These reactions have applications in the synthesis of natural products and pharmaceuticals, and further research is needed to develop new transformations and expand their applications. [Extracted from the article]

The article discusses the synthesis of P-chiral tertiary phosphine oxides through copper-catalyzed dynamic kinetic asymmetric C-P cross-coupling. P-stereogenic compounds are important in various fields, but their conventional synthesis methods have limitations. The use of secondary phosphine oxides (SPOs) as an alternative reagent has been explored, but challenges such as racemization and side reactions remain. The authors developed a copper catalyst and optimized reaction conditions to achieve highly enantioselective C-P coupling reactions, resulting in a wide range of P-stereogenic compounds with high yields and enantioselectivities. The resulting compounds can be further transformed into structurally diverse P-chiral scaffolds. The article also highlights the limitations and areas for future research in this field. [Extracted from the article]

This article discusses the synthesis and characterization of various phosphonate compounds. The authors developed a method using a boron Lewis acid catalyst to add the P-H bond of alkenes with H-phosphonates, resulting in the formation of β-N-heteroaryl alkylphosphonates. The document provides detailed information on the preparation, purification, and physical properties of these compounds, as well as spectroscopic data such as NMR spectra and IR spectra. The compounds synthesized have potential applications in various fields. The authors are researchers in the field of organic chemistry with a focus on catalysis. [Extracted from the article]

This article provides an overview of synthetic strategies for accessing dibenzophosphole scaffolds, which are important in the development of π-conjugated organic materials. The article categorizes the synthetic strategies into three types based on the formation of the phosphole skeleton and fused-benzene rings. It discusses various reaction types and provides specific examples of each method. The article emphasizes the bond formation processes and does not mention the valence and charge of the phosphorus atom unless necessary. The text discusses various methods for the synthesis of dibenzophosphole derivatives, including lanthanum heterocycles, phospha-Friedel-Crafts reactions, McCormack reactions, intramolecular P-C bond formation, and transition-metal-catalyzed approaches. It also mentions methods such as PFC reactions, S Ni reactions, alkali metal-mediated cyclization, and P-H/C-H coupling. The article further discusses methods like oxidative cyclization, copper-mediated cyclization, manganese-catalyzed and manganese-mediated cyclization, electrosynthesis, and intramolecular C-C bond formation. Palladium-catalyzed approaches are also mentioned, including C-Br/C-Br coupling and C-H/C-X coupling. The authors provide detailed reaction schemes and mechanisms for each method. The article highlights the need for more efficient and precise protocols for constructing the dibenzophosphole framework and suggests that these methods could lead to the discovery of new molecular scaffolds for functional materials. [Extracted from the article]

This document summarizes a study on the synthesis of difluoromethylene-containing compounds, which are important in drug design. The researchers focused on the regio- and enantioselective bromocyclization of difluoroalkenes, using a chiral bisphosphine oxide catalyst. They found that the reaction was highly selective and enantioselective, producing unique oxazines with high yields. The researchers believe that this method could be used to create new bioactive compounds, although further investigation is needed to understand the mechanism of the reaction. [Extracted from the article]

This article discusses the use of nickelacycles as catalysts in the conjugate addition of organoboron compounds to ¿,ß-unsaturated ketones. The authors synthesized two different nickelacycles and evaluated their catalytic activity in this reaction. They found that the nickelacycles showed higher activity compared to corresponding palladacycles. The study provides insights into the deactivation pathways of the catalyst and compares the catalytic activity of nickelacycles with other catalysts. Overall, the research demonstrates the potential of nickelacycles as catalysts in carbon-carbon bond formation reactions. [Extracted from the article]

Finally, hydroboration of the enol carbamates derived from citronellal demonstrated a matched/mismatched effect wherein the I S i -methyl isomer was formed with a substantially higher dr than the I R i -methyl isomer. Keywords: hydroboration; Matteson homologation; Julia olefination; boronic esters; rhodium catalysis EN hydroboration Matteson homologation Julia olefination boronic esters rhodium catalysis 2181 2186 6 10/31/23 20231127 NES 231127 Graph The Matteson homologation remains a valuable synthetic transformation and a subject of continuing development 60 years after its initial disclosure. [28] We reasoned that asymmetric hydroboration of enol carbamates might produce -boryl carbamates with equal access to either enantiomer and a requirement for only catalytic quantities of the chiral controller (Scheme 1 F). [Extracted from the article]

Keywords: phosphinates; P-stereogenic centers; nickel catalysis; cross-coupling; asymmetric catalysis EN phosphinates P-stereogenic centers nickel catalysis cross-coupling asymmetric catalysis 1819 1823 5 08/29/23 20230915 NES 230915 Graph P-Stereogenic organic phosphorus compounds, especially chiral phosphinic acid derivatives, are useful in medicinal chemistry, pesticide chemistry, organic materials science, and biochemistry. Moreover, when we employed aryl iodides with a free amino ( B 26 b ) or hydroxy group ( B 27 b ) at the I para i -position of the aryl ring, P-chiral phosphinates were obtained in moderate yields (71 and 68%) and high ee values (88 and 81% ee). [41] However, we found aryl iodides with different electronic properties all gave the corresponding P-chiral phosphinates with moderate to high ee values (62-82% ee); in other words, the enantioselectivity was only slightly affected by the electronic properties of the aryl iodides. During the preparation of our manuscript, Duan and our group separately reported Ni(0)-catalyzed intermolecular reactions of nonactivated aryl halides [39] and Ni(II)-catalyzed intermolecular reactions of heterocyclic halides, [40] respectively. [Extracted from the article]

4-Formylphenyldiphenylphosphine (3f') 6a According to GPC using 4-bromobenzaldehyde (37 mg, 0.2 mmol, 1.0 equiv), CuCl SB 2 sb (2.7 mg, 0.02 mmol), 4-methylbenzoyldiphenylphosphine (61 mg, 0.2 mmol, 1.0 equiv), DMEDA (6.6 L, 0.06 mmol, 0.3 equiv), Cs SB 2 sb CO SB 3 sb (71 mg, 0.22 mmol, 1.1 equiv), and toluene (0.4 mL) afforded B 3f' b (46 mg, 80%) as a white amorphous solid. 3-(Diphenylphosphino)benzonitrile (3g') 11 According to GPC using 3-bromobenzonitrile (36 mg, 0.2 mmol, 1.0 equiv), CuCl SB 2 sb (2.7 mg, 0.02 mmol), 4-methylbenzoyldiphenylphosphine (61 mg, 0.2 mmol, 1.0 equiv), DMEDA (6.6 L, 0.06 mmol, 0.3 equiv), Cs SB 2 sb CO SB 3 sb (71 mg, 0.22 mmol, 1.1 equiv), and toluene (0.4 mL) afforded B 3g' b (30 mg, 52%) as a white amorphous solid. 4-(Diphenylphosphino)pyridine (3h') 6a According to GPC using 4-bromopyridine hydrochloride (38.9 mg, 0.2 mmol, 1.0 equiv), CuCl SB 2 sb (2.7 mg, 0.02 mmol), 4-methylbenzoyldiphenylphosphine (61 mg, 0.2 mmol, 1.0 equiv), DMEDA (6.6 L, 0.06 mmol, 0.3 equiv), Cs SB 2 sb CO SB 3 sb (71 mg, 0.22 mmol, 1.1 equiv), and toluene (0.4 mL) afforded B 3h' b (40 mg, 76%) as a white amorphous solid. Keywords: Cu catalysis; acylphosphines; C(sp 2)-P bond formation; triarylphosphine; phosphination reagent EN Cu catalysis acylphosphines C(sp 2)-P bond formation triarylphosphine phosphination reagent 2586 2594 9 07/31/23 20230817 NES 230817 Graph Triarylphosphines are widely used as ligands [1] and catalysts [5] for tuning chemo-, regio-, and stereoselectivities of organic reactions. [Extracted from the article]

2 Triplet Ketone Catalysis via Hydrogen Atom Transfer 2.1 Triplet Ketones with Nickel Catalysis Arguably, the employment of light-excited ketones as HAT agents is the most abundant application among all types of triplet ketone catalysis. 3 Triplet Ketone Catalysis via Single-Electron Transfer As mentioned in the introduction section, the oxidative abilities of triplet ketones grant their applicability as oxidants in SET events with substrates or other reaction intermediates. Keywords: dual catalysis; triplet ketone; transition-metal catalysis; photocatalysis; photosensitizer; C-H functionalization EN dual catalysis triplet ketone transition-metal catalysis photocatalysis photosensitizer C-H functionalization 1289 1308 20 07/11/23 20230725 NES 230725 Graph 1 Introduction Over the last few decades, aromatic ketones have gained increased attention as inexpensive organic photocatalysts with highly tunable photophysical properties. In 2020, Li's group disclosed the synthesis of ketones via decarboxylative coupling of -keto acids with aryl halides by employing CFL-induced triplet ketone/Ni catalysis (Scheme 20). [Extracted from the article]

Keywords: chirogenic compounds; phosphine oxides; binaphthyl phosphonates; chirality transfer reaction; one-pot reaction EN chirogenic compounds phosphine oxides binaphthyl phosphonates chirality transfer reaction one-pot reaction 1502 1506 5 07/11/23 20230725 NES 230725 Graph Increasing attention has been paid to the development of new methods [1] for the synthesis of P-chirogenic secondary and tertiary phosphine oxides, because of their wide applicability as optically active ligands, [4] nucleophilic catalysts, [7] and drug candidates. [44] In the reaction of phosphonates B I b with Grignard reagents, the axial chirality of the binaphthyl group has been efficiently transferred to the central chirality of the phosphorus atom in the products B II b (Scheme 1). [28] Alternatively, a stereoselective substitution reaction at the phosphorus atom of P-chirogenic tertiary phosphine oxides with a chiral auxiliary at the phosphorus atom is possible. [Extracted from the article]

The second step corresponds to the decarboxylation of B I Int-1a i b , where the topological changes consist of a high increase of the V(O1) and V(N1) basin populations coming from breaking the O1-P2 [disappearance of V(O1,P2) basin at the SSD-II] and N1-C2 bonds [disappearance of V(N1,C2) basin at the SSD-III]. Keywords: Wittig reaction; bonding evolution theory; DFT calculations; 2-methylbenzothiazole synthesis; aza-Wittig EN Wittig reaction bonding evolution theory DFT calculations 2-methylbenzothiazole synthesis aza-Wittig 2070 2082 13 06/16/23 20230704 NES 230704 1 Introduction The notion of chemical bonding that seems so obvious today appeared in the second half of the 19th century and has evolved over centuries. At the end the domain [ I d i (O1-C2) = 1.395 Å and I d i (N1-P2) = 1.908 Å], the population of V(N1) equals 1.17e while V(O1,C2) and V(N1,P2) are populated by 1.57 and 2.54e, respectively. The transition from domain SSD-I [ I d i (O1-P2) = 2.057 Å and I d i (N1-C2) = 1.443 Å] to SSD-II [ I d i (O1-P2) = 2.089 Å and I d i (N1-C2) = 1.447 Å] deals with the breaking of the O1-P2 bond with the transfer of its electron population to the O1 lone pair. [Extracted from the article]

A palladium-catalyzed tandem cyclization reaction was developed, which offers a pragmatic synthesis of aminated tetracyclic 1,2-benzothiazepine 1-oxides bearing a highly fused medium-sized cyclic unit. An acetyl (Ac) group was found to be the optimal protecting group for sulfoximines to reduce the nucleophilic ability of the N atom, thus efficiently suppressing the formation of intramolecular 5- exo - dig cyclization side products. The transformation proceeds through a double syn -carbopalladation/annulation sequence to construct the rigid tetracyclic carbo-heterocyclic framework with excellent chemoselectivity and regioselectivity. [ABSTRACT FROM AUTHOR]

This work presents the first enantio- and diastereoselective assembly of multi-layer folding targets through asymmetric catalytic C–C bond formation. Pd[(S)-BINAP]Cl2 is found to be an efficient catalyst for the Suzuki–Miyaura coupling between phosphinyl bromides and benzothiadiazole boronic esters for this asymmetric assembly. The structure of the resulting chiral multi-layer folding framework is unambiguously determined by X-ray analysis and shows a nearly parallel pattern of three layers and quasi- syn and - anti configurations. Good to excellent diastereo- and enantioselectivities (up to >20:1 dr and >99:1 er) are achieved. [ABSTRACT FROM AUTHOR]

An enantioselective β-silylation of α,β-unsaturated phosphine oxide derivatives using a silylboronic ester as the silicon pronucleophile is reported. The reaction is catalyzed by copper salts in the presence of chiral pyridine–oxazoline (PyOx) ligands. Good to high enantioselectivities (≤95% ee) are obtained for β-aryl-substituted acceptors whereas alkyl residues in the β-position led to a lower ee value for 1° and no reaction for 2° and 3°. The new method represents another way of accessing α-chiral silanes and complements the known β-borylation. [ABSTRACT FROM AUTHOR]

Trifluoromethanesulfonic anhydride (Tf2 O) is utilized as a strong electrophilic activator in a wide range of applications in synthetic organic chemistry, leading to the transient generation of a triflate intermediate. This versatile triflate intermediate undergoes nucleophilic trapping with diverse nucleophiles to yield novel compounds. In this review, we describe the features and applications of triflic anhydride in organic synthesis reported in the past decade, especially in amide, sulfoxide, and phosphorus oxide chemistry through electrophilic activation. A plausible mechanistic pathway for each important reaction is also discussed. 1 Introduction 2 Amide Chemistry 2.1 Carbon Nucleophiles 2.2 Hydrogen Nucleophiles 2.3 Nitrogen Nucleophiles 2.4 Oxygen and Sulfur Nucleophiles 2.5 hosphorus Nucleophiles 2.6 A Vilsmeier-Type Reagent 2.7 Umpolung Reactivity in Amides 3 Sulfoxide Chemistry 3.1 Oxygen Nucleophiles 3.2 Carbon Nucleophiles 3.3 Nitrogen Nucleophiles 3.4 Thionium Reagents 4 Phosphorus Chemistry 4.1 Hendrickson's Reagent 4.2 Diaryl Phosphine Oxides 4.3 Phosphonates, Phosphates and Phosphinates 5 Conclusion and Outlook [ABSTRACT FROM AUTHOR]

A series of 2-(hetero)aryl-4-phosphorylated quinazolines was successfully synthesized in moderate to excellent yields via a palladium-catalyzed C–O/P–H cross-coupling reaction of 4-(tosyl-oxy)quinazolines with H-phosphonates and phosphine oxides. This efficient and green methodology provides an alternative straightforward protocol for the introduction of phosphorus groups to quinazoline compounds at the C4 position via C–O activation. [ABSTRACT FROM AUTHOR]

The synthesis of a new family of pentacoordinated spiro[4.4]phosphoranes stabilized by the ortho -benzamide bidentate ligand (o BA, -C6 H4-2-C(O)NH-) through reaction of Cα ,C ortho -dilithiated phosphazenes with oxiranes is reported. Mixtures of epimers that differ in configuration at the phosphorus atom were obtained with moderate to high yields and diastereoselectivities. C3-Disubstituted derivatives could be separated, which provided access to enantiopure products arising from the reaction with (R)-2-phenyloxirane. Stereomutation was observed by heating the spirophosphoranes at 100 °C. Directed ortho -lithiation of spirophoshoranes followed by electrophilic quench reactions including carbon-based and heteroatom-based electrophiles afforded derivatives functionalized in a remote position with respect to the phosphorus atom. Benzoic acid catalyzed hydrolysis of spirophosphoranes furnished ortho -(γ-hydroxyalkylphosphoryl)benzamides by cleavage of the P–O and P–N bonds with retention of the phosphorus configuration. In contrast, alkaline hydrolysis led to the formation of γ-hydroxyphosphinic acids and benzamide. [ABSTRACT FROM AUTHOR]

P-Stereogenic secondary phosphine oxides [SPOs, RR′P(O)H], valuable ligands for metal complexes in asymmetric catalysis, are also building blocks for other chiral phosphorus derivatives. This short review summarizes methods used for asymmetric synthesis of P-stereogenic SPOs. 1 Introduction 2 Configurational Stability of P-Stereogenic SPOs 3 Classical Resolution, HPLC Separation, and Dynamic Resolution 4 Synthesis via Chiral Auxiliaries 5 Kinetic Resolution 6 Conclusions and Outlook [ABSTRACT FROM AUTHOR]

The distinguishing feature of α-cationic phosphines is the presence of at least one substituent, normally (hetero)cyclic and positively charged, which is directly attached to the phosphorus atom. As result from this unique substitution pattern, the thus designed ligands depict significantly diminished donor properties if compared with their neutral counterparts. Thus, if in a hypothetical catalytic cycle, the step that determines the rate is facilitated by an increase of the electrophilicity at the metal center; then, the use of α-cationic ancillary phosphines can be highly beneficial. This fact, combined with their easy syntheses and stability, which allows an easy handling, make α-cationic phosphines a useful tool for the synthetic practitioner. Our research on the topic demonstrates that generally a remarkable ligand acceleration effect is observed when α-cationic phosphines are employed in Au(I)- and Pt(II)-promoted cycloisomerizations; moreover, in some cases even otherwise not operative transformations can be promoted. This Account describes how we entered into the topic, our efforts, and those of others to understand the coordination behavior of α-cationic phosphines and further develop their range of applications in catalysis; but it also identifies the drawbacks associated with their use, which limit their range of application. 1 Introduction 2 Polycationic Phosphines: Stronger Acceptors than Phosphites 3 Inconveniences Derived from the Use of (Poly)cationic phosphines 4 A Second Generation of Cationic Ligands: α-Pyridiniophosphines 5 Chiral α-Cationic Phosphines 6 α-Radical Phosphines and (Poly)cationic Phosphine Oxides 7 Conclusions and Outlook [ABSTRACT FROM AUTHOR]

We describe a method for the preparation of CF2-P(V) building blocks and monomers for biological and materials chemistry applications in multigram quantities based on a formal [2,3]-sigmatropic phospha-Wittig rearrangement of readily available fluoroallyl bis(amido)phosphites, amido(aryl)phosphonites, and diarylphosphinites. The proposed intramolecular phosphorylation approach complements the currently prevailing phosphoryldifluoromethylation methods by providing a straightforward access to difluoromethylene phosphonate analogues bearing dialkylamino and/or aryl substituents at the phosphoryl group. An important advantage of the developed method is that it does not rely on ozone-depleting HCF2 Cl and CF2 Br2 necessary for the preparation of phosphoryldifluoromethylating reagents. 2,3,3-Trifluoroallyloxy P(III) derivatives substituted with two dialkylamino and/or aryl groups underwent a facile [2,3]-rearrangement to give difluoromethylene phosphonic and phosphinic amides and phosphine oxides on up to a 0.15 mol (30 g) scale. The reaction was extended to P(III) derivatives of 1-substituted 2,3,3-trifluoro- and 3,3-difluoroallylic alcohols readily available from carbonyl compounds and, respectively, 1,1,1,2-tetrafluoroethane and O -protected 2,2,2-trifluoroethanols. Products derived from O -(tetrahydropyran-2-yl)-2,2,2-trifluoroethanol were synthesized and deprotected in a one-pot multistep protocol to give phosphonic and phosphinic amide and phosphine oxide analogues of α,α-difluoro-β-ketophosphonates on a multigram scale. [ABSTRACT FROM AUTHOR]

Herein, NiCl2 is employed as a cheap precatalyst in the formation of C(sp2)–P bond via cross-coupling reaction of phenol derivatives and phosphine oxides/phosphites. This catalytic system allows a variety of phenols with diverse functional groups to transform into phosphates with good yields. No additional additive is used in this reaction. [ABSTRACT FROM AUTHOR]

A wide range of commercially available aldehydes have been applied to Knoevenagel condensation reaction to give E -alkenylphosphine oxides and vinylphosphine oxides. The readily available phosphinoylacetic acids derived from P(O)–H compounds were used as the starting materials in the reaction, providing a highly stereoselective and efficient method for constructing α,β-unsaturated phosphine oxides. Moreover, this simple and practical procedure provides an alternative and more environmentally friendly synthesis strategy for this type of P-functionalized alkenyl compounds. [ABSTRACT FROM AUTHOR]

A transition-metal-free t -BuOK-mediated reductive C–P cross-coupling reaction of arylvinyl sulfides with diarylphosphine oxides through C–S bond cleavage has been developed. This protocol not only permits the synthesis of diaryl(2-arylethyl)phosphine oxides, but also achieves an unprecedented construction of a C–P bond through C–S bond cleavage and reduction of a C–C double bond in one pot. [ABSTRACT FROM AUTHOR]

The recently reported chemoselective reduction of phosphine oxides with 1,3-diphenyldisiloxane (DPDS) has opened up the possibility of additive-free phosphine oxide reductions in catalytic systems. Herein we disclose the use of this new reducing agent as an enabler of phosphorus redox recycling in Wittig, Staudinger, and alcohol substitution reactions. DPDS was successfully utilized in ambient-temperature additive-free redox recycling variants of the Wittig olefination, Appel halogenation, and Staudinger reduction. Triphenylphosphine-promoted catalytic recycling reactions were also facilitated by DPDS. Additive-free triphenylphosphine-promoted catalytic Staudinger reductions could even be performed at ambient temperature due to the rapid nature of phosphinimine reduction, for which we characterized kinetic and thermodynamic parameters. These results demonstrate the utility of DPDS as an excellent reducing agent for the development of phosphorus redox recycling reactions. [ABSTRACT FROM AUTHOR]

Nonsymmetric tertiary phosphine oxides with different five- and six-membered heterocyclic fragments such as pyridine, 2,2′-bipyridine, 1,10-phenantroline, quinoline, imidazole, and thiazole were synthesized in good yields via the successive introduction of phosphine oxide groups into the initial dihalogenated heterocycles by means of Pd-catalyzed phosphorylation reaction. The synthesis of pyridine-type compounds is hindered by competing double coupling, while for five-membered heterocycles the principal difficulty is the dehalogenation. Both side processes were successfully suppressed by the use of an excess of a dihalide (which can be easily recovered during the product purification step), proper phosphine ligand for palladium, and nonpolar solvent such as toluene. [ABSTRACT FROM AUTHOR]

The transition-metal complexes of phosphine and secondary phosphine oxide compounds can be used in various catalytic reactions. In this paper, the synthesis and characterization of eight new crown ethers containing trivalent phosphorus in their macroring are reported. These macrocycles are promising candidates as ligands for catalytic reactions. [ABSTRACT FROM AUTHOR]

Tertiary α-hydroxyphosphine oxides have been synthesized via the catalyst- and solvent-free reaction between available secondary phosphine oxides and aliphatic, aromatic and heteroaromatic ketones at 20–62 °C in near to 96–98% yield. The developed method meets the requirements of green chemistry and the PASE (pot, atom, step economy) paradigm. According to quantum-chemical calculations at the B3LYP/6-311++G(d,p) level, the synthesized hydroxyphosphine oxides feature a weak (≈3 kcal·mol–1) O−H···O=P intramolecular hydrogen bond. [ABSTRACT FROM AUTHOR]

This account summarizes the development of new biheteroaromatic chiral bisphosphine oxides. 3,3′-Bithiophene-based phosphine oxides (BITIOPOs) have been successfully used as organocatalysts to promote Lewis base catalyzed, Lewis acid mediated stereoselective transformations. These highly electron-rich compounds, in combination with trichorosilyl derivatives (allyltrichlorosilane and silicon tetrachloride), generate hypervalent silicon species that act as chiral Lewis acids in highly diastereo- and enantioselective organic reactions. Several relevant examples related to these applications are discussed in detail. 1 Introduction 2 The BITIOPO Family 3 Enantioselective Opening of Epoxides 4 Enantioselective Allylation of Aldehydes 5 Stereoselective Direct (Double) Aldol-Type Reaction with Ketones 6 Stereoselective Direct Aldol-Type Reaction with Ester Derivatives 7 Conclusions [ABSTRACT FROM AUTHOR]

A practical protocol for efficient synthesis of both PAMPO enantiomers as well as related functionalised P-stereogenic phosphine oxides in 1–3 steps from effectively resolved (S P)- l -menthyl o -anisyl--(phenyl)phosphinylacetate has been developed. Examples of non-stereo-selective quaternisation of a tertiary phosphine by alkyl halides have been revealed. [ABSTRACT FROM AUTHOR]

An alternative metal-free, efficient and practical approach for the preparation of phosphinothioates is established via the aerobic oxidative cross-dehydrogenative coupling (CDC) of sulfonyl hydrazides with secondary phosphine oxides catalyzed by tetrabutylammonium iodide (TBAI) in the presence of atmospheric oxygen. The strategy provides an array of diverse phosphinothioates in good to excellent yields. Furthermore, two representative bioactive molecules are synthesized on up to gram scale by utilizing this method. [ABSTRACT FROM AUTHOR]

α,β-Unsaturated phosphine sulfides may exhibit different reactivity from α,β-unsaturated phosphine oxides toward nucleophilic addition and thus may find new applications in copper(I)-catalyzed asymmetric reactions. Herein, various α,β-unsaturated phosphine sulfides were prepared in moderate to excellent yields from the parent α,β-unsaturated phosphine oxides with Lawesson's reagent. The reaction enjoys a broad substrate scope and tolerates a variety of functional groups. [ABSTRACT FROM AUTHOR]

We report the development of an electrocatalytic protocol for the chlorophosphinoylation of simple alkenes. Driven by electricity and mediated by a Mn catalyst, the heterodifunctionalization reaction takes place with high efficiency and regioselectivity. Cyclic voltammetry data are consistent with a mechanistic scenario based on anodically coupled electrolysis in which the generation of two distinct radical intermediates occur simultaneously on the anode and are both mediated by the Mn catalyst. [ABSTRACT FROM AUTHOR]

An efficient procedure for C–P bond formation via the palladium-catalyzed [Pd(OAc)2 /dppf/Cs2 CO3 ] reaction between dichloroheterocycles and secondary phosphine oxides was developed. The steric and electronic properties of substituents were varied to establish the scope and limitations of the method developed. By applying these conditions, a variety of new heterocyclic compounds bearing two tertiary phosphine oxides were successfully synthesized in moderate to excellent yields. After adjustments to the reaction conditions [Pd(OAc)2 /dippf/ t -BuOK], cross-coupling of secondary phosphine oxides with bulky (secondary or tertiary alkyl) substituents on the phosphorus atom was achieved. Extension of the methodology to monohalohetarenes and monohaloarenes was successfully carried out; once again, the steric and electronic properties of the halides were varied widely. The desired reaction occurred in all cases studied, giving high to excellent yields of product regardless of the nature and positions of substituents. [ABSTRACT FROM AUTHOR]

Air- and moisture-stable secondary phosphine oxides (SPOs) enabled nickel-catalyzed Kumada–Corriu cross-couplings of various arylmethyl ethers at room temperature by challenging C–O activation. [ABSTRACT FROM AUTHOR]

We have developed a simple method for the oxyphosphorylation of arylalkynes to give β-keto phosphine oxides without the assistance of any transition metal. An inorganic base promoted the oxyphosphorylation and water played a synergistic role in the formation of various β-keto phosphine oxides. The reaction showed a wide structural scope and broad functional-group tolerance, and it proceeded under mild reaction conditions. This method solved the problem of metal dependence in the oxyphosphorylation of alkynes, providing a potential application in organic chemistry. Control experiments revealed the mechanism of the oxyphosphorylation and the synergistic role played by water in the radical process. [ABSTRACT FROM AUTHOR]

Tertiary sulfanylphosphine and aminoalkylphosphine oxides can be easily converted into the corresponding tertiary sulfanylphosphine- and aminoalkylphosphine-boranes, respectively, through the facile P=O bond reduction by borane complexes. The easy reduction of the strong P=O bond by BH3, a mild reducing agent, has been achieved through an intramolecular P=O -- B complexation directed by proximal SH or NH activating groups located at the α- or β-position to the P=O bond. A generalized reduction mechanism has been proposed. [ABSTRACT FROM AUTHOR]

Traditional methods for C-P bond formation via direct addition of P-H species to unsaturated compounds are usually implemented in the presence of base and metal catalysts or radical initiators in various organic solvents. During the last five years, a novel efficient and general catalyst/initiator- and solvent-free version of the hydrophosphination and hydrophosphinylation of multiple C-C bonds with H-phosphines and their chalcogenides has begun to develop and it is attracting growing attention. This approach corresponds to the recently emerged pot-, atom-, and step-economy (PASE) green paradigm. This review covers the literature on the synthesis of useful and in-demand organophosphorus compounds via catalyst- and solvent-free addition of P-H species to alkenes and alkynes. 1 Introduction 2 Addition of Secondary Phosphines to Alkenes 3 Hydrophosphinylation of Alkenes with Secondary Phosphine Chalcogenides 3.1 Oxidative Addition of Phosphine Oxides to Vinyl Sulfides 3.2 Addition of Secondary Phosphine Sulfides and Phosphine Selenides to Alkenes 3.3 Addition of Secondary Phosphine Sulfides and Phosphine Selenides to Divinyl Chalcogenides 3.4 Hydrophosphinylation of Alkenes with Secondary Phosphine/Chalcogen Pair (Three-Component Reactions) 4 Addition of Secondary Phosphines to Alkynes 5 Addition of Secondary Phosphine Chalcogenides to Alkynes 6 Conclusion. [ABSTRACT FROM AUTHOR]

Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TMDPO) is a radical initiator widely used in the field of macromolecular chemistry, but not often applied in synthetic organic chemistry. We have focused on the use of TMDPO as a phosphorus source in reactions with different E-E compounds, where E-E represents a heteroatom- heteroatom bond, under photoirradiation. Interestingly, the cross-coupling reaction between TMDPO and disulfides or diselenides successfully affords thio- or selenophosphinates and thio- or selenoesters, respectively. The synthesis of series of thio- and selenophosphinates by this photoinduced cross-coupling reaction is demonstrated. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed intramolecular direct arylation reaction of o-bromoaryl phosphine oxides was developed to afford a variety of P-stereogenic phosphole oxides in good yields. The enantioselectivities were closely associated with the specific structures of substrates, which ranged from 4-94%. As a result of ready availability of starting materials and simple operation to improve the enantioselectivities of the products with low ee values, the method provides a simple and straightforward procedure for the synthesis of P-stereogenic phosphole oxides. [ABSTRACT FROM AUTHOR]

The interaction of 1-alkynyl phosphine oxides, sulfides, and selenides with Me3Al and Et3Al under zirconocene catalysis was studied. It has been found that the pathway of the reaction of 1-alkynyl phosphine derivatives with Et3Al strongly depends on the nature of the substrate and the solvent. The ethylalumination takes place in the case of 1-alkynyl phosphine oxides in hexane solvent. The reaction of 1-hexynyl phosphine oxide with Et3Al failed when dichloromethane was used as a solvent. Zirconium-catalyzed reaction of 1-heptynyl phosphine sulfide with Et3Al proceeds as the cycloalumination followed by the desulfurization under the action of low-valent zirconium complexes. 1-Heptynyl phosphine selenide was subjected to full deselenation under the reaction conditions. [ABSTRACT FROM AUTHOR]

An efficient one-pot access to di(2-pyridyl)phosphine oxides Py2P(R)=O and bis[di(2-pyridyl)phosphine oxides] Py2P(O)-Z-P(O)Py2 has been developed based on the reaction of available tris(2-pyridyl) phosphine with various organic halides, followed by treatment of the resulting phosphonium salts with alkali in situ. The isolated yields of the phosphine oxides were in the range 40-96%. [ABSTRACT FROM AUTHOR]