Annie-Claude Gaumont

• École Nationale Supérieure d'Ingénieurs de Caen

The reactions of planar chiral ([2.2]paracyclophan‐4‐yl)methyl thioethers ([2.2]PCP‐CH2‐SR) with various palladium(II) sources (PdL2) were studied. Unexpectedly, with most of the sulfur substrates investigated (SR=Ph, 2‐pyridyl, Me, n‐dodecyl), and independently of the PdL2 salt employed (L=TFA, OAc, OPiv, Cl, Br), loss of the SR sulfanyl unit, alo...

Regioselective phosphonation of pyridines is an interesting transformation in synthesis and medicinal chemistry. We report herein a metal-free approach enabling access to various 4-phosphonated pyridines. The method consists of simply activating the pyridine ring with a Lewis acid (BF3·OEt2) to facilitate the nucleophilic addition of a phosphine ox...

In this work, the design and characterization of new supported ionic liquid membranes, as medium-temperature polymer electrolyte membranes for fuel-cell application, are described. These membranes were elaborated by the impregnation of porous polyimide Matrimid® with different synthesized protic ionic liquids containing polymerizable vinyl, allyl,...

We report herein an unprecedented combination of light and P(III)/P(V) redox cycling for the efficient deoxygenation of aromatic amine N‐oxides. Moreover, we discovered that a large variety of aliphatic amine N‐oxides can easily be deoxygenated by using only phenylsilane. These practically simple approaches proceed well under metal‐free conditions,...

An expeditious route to planar chiral sulfur-based scaffolds has been achieved in two operational steps from cheap and commercial [2.2]paracyclophane hydrocarbon. The sulfur atom was introduced in a specific benzylic position of the [2.2]paracyclophane according to a reductive sulfanylation reaction, which proceeds under two complementary reaction...

Considering the synthetic relevance of heteroarenes in various areas ranging from organic synthesis to medicinal chemistry, developing practically simple methodologies to access functionalized heteroarenes is of a significant value. Described herein is an efficient approach for C–H silylation and hydroxymethylation of pyridines and related heterocy...

Advances in the field of phosphorus chemistry are documented, by revealing the synthetic utility of previously underutilized quaternary phosphiranium salts (QPrS) as three‐chain‐atom electrophilic building blocks. Notably, control of their challenging C‐centered electrophilicity is disclosed with an expedient synthesis of tertiary β‐anilino phosphi...

C versus P selectivity: Quaternary phosphiranium salts (QPrS) are a fascinating yet underutilized class of phosphorus building blocks with instability and site‐electrophilicity issues. The challengingC‐centered nucleophilic ring opening of these salts, by reaction with aniline derivatives, is now reported and demonstrates the potential synthetic ut...

We report the preparation of phosphiranium salts by quaternarization of phosphiranes, a class of sensitive, highly strained, and poorly nucleophilic cyclic phosphines. High-yielding introduction of a varied set of alkyl groups including methylene ester arms was accomplished under mild conditions. A Cu-catalyzed electrophilic arylation of phosphiran...

A series of polyaromatic naphthalenes have been synthesized through the dehydrogenation of the corresponding 1,2‐dihydroarylnaphthalenes by using 9‐mesityl‐10‐methylacridinium perchlorate as a photocatalyst and diphenyliodonium triflate as an external oxidant under visible light irradiation. The reaction proceeds smoothly under metal‐free condition...

This work reports a simple and efficient method for the direct phosphorylation of enamide under metal-free conditions. The P-centered radicals, derived from secondary phosphine oxides, are generated under mild reaction conditions in the presence of diphenyliodonium salt and Et3N and are introduced onto a range of enamides in good isolated yields. T...

Unambiguously confirmed by low‐temperature in situ NMR experiments, X‐ray diffraction and vibrational spectroscopy, phosphonium‐carbenium superelectrophiles are shown to be generated in strong acidic conditions. Representing crucial intermediates, their exploitation allows for the synthesis of unprecedented fluorinated (cyclic) phosphine oxides.

In the present work, we report the efficiency of the commercially available [(PPh3)AuCl] complex in combi-nation with a set of potassium salts to catalyze the hydroarylation of a broad variety of alkenes usingN,N-dialkylanilines, leading to full conversion and complete selectivity toward the Markovnikov products. Thecombination of experimental info...

This work describes an efficient alpha–phosphorylation of a wide variety of N–aryl tertiary amines under mild conditions. It consists of a simple combination of amines (electron donors) with N-ethoxy-2-methylpyridinium tetrafluoroborate...

Unambiguously confirmed by low‐temperature in situ NMR experiments, X‐ray diffraction and vibrational spectroscopy, phosphonium‐carbenium superelectrophiles are shown to be generated in strong acidic conditions. Representing crucial intermediates, their exploitation allows for the synthesis of unprecedented fluorinated (cyclic) phosphine oxides. To...

This work describes a straightforward access to a large variety of aryl phosphonates by the simple combination of diaryliodonium salts with phosphites in the presence of a base and under visible-light illumination. The reaction proceeds smoothly, tolerates various functionalities, and was applied for the synthesis of pharmaceutically relevant compo...

An operationally simple methodology for the synthesis of 4‐sulfonyl‐3‐pyrrolines is described using a propargylic sulfone and N‐sulfonyl imines as substrates. This annulation process is initiated by an arenesulfinate organocatalyst, which allows a smooth isomerization of the alkynyl precursor into the corresponding allene, followed by the generatio...

The benzenesulfinate‐catalyzed (3+2) annulation between allenyl sulfones and aryl(alkyl)idenemalononitriles has been developed under mild phase transfer conditions, affording a breadth of functionalized sulfonyl cyclopentenes in good to excellent yields (22 examples, 49–99%) and high diastereoselectivities. These adducts were likely generated, via...

The synthesis and identification of unprecedented gem-dianionic phosphorus compounds, i.e. gem-dilithium phosphido-boranes Li2[RP*BH3], with R = Ph or Cy, are reported in THF solution. Those are obtained by double deprotonation of the corresponding primary phosphine-borane precursors RPH2*BH3. Their in-depth structural study, based on multinuclear...

A new class of catalytic ionogels based on the entrapment of an ionic liquid phase within a sodium alginate matrix was applied to the Pd-catalyzed allylic substitution reaction. High activity and promising recyclability were obtained in C-N bond formation. Scanning electron microscopy, scanning transmission electron microscopy and solid-state NMR s...

This study reports the ring-closing metathesis reaction of bisolefins, including a reluctant fluoroalkenes, linked with oxaza moiety. The resulting heterocycles were produced in high yields under high diluting conditions disfavoring the homodimerization side reaction of nonfluorinated double bond. The use of a mixture of solvents proved to be a goo...

This short review describes our recent efforts to generate phosphorus-based radicals under metal-free conditions and their use as key intermediates for the synthesis of phosphorus-based heterocycles. In this regard, the synthesis of benzo[b]phosphole oxides and 6-phosphorylated phenanthridines will be reported. While the synthesis of the former lie...

A catalytic intramolecular silapalladation of alkynes affords, in good yields and stereoselectively, syn-disilylated heterocycles of different chemical structure and size. When applied to silylethers, this reaction leads to vinylic silanols that undergo a rhodium-catalyzed addition to activated olefins, providing the oxa-Heck or oxa-Michael product...

We report a new procedure for the preparation of NH-sulfoximines from sulfides using PIDA as an oxidant and ammonium carbamate as the ammonia source. Excellent yields were obtained with a wide range of sulfides. The formation of acetoxy- and methoxy-λ(6)-sulfanenitrile as intermediates was proposed, both of which were converted to the NH-sulfoximin...

This work describes the first transition metal-free stereospecific synthesis of (E)-(1-fluoro-2-arylvinyl)phosphine boranes through the addition of diarylphosphine-boranes to gem-bromofluoroalkenes in the presence of a base at room temperature. The reaction proceeds well under very mild conditions and tolerates a variety of functionalities. Scope a...

A catalytic intramolecular silapalladation of alkynes affords, in good yields and stereoselectively, syn-disilylated heterocycles of different chemical structure and size. When applied to silylethers, this reaction leads to vinylic silanols that undergo a rhodium-catalyzed addition to activated olefins, providing the oxa-Heck or oxa-Michael product...

Frustrated Lewis pair (FLP)-catalyzed reduction of Michael acceptors is a challenging reaction that proceeds with specific FLP structures. Kinetics and equilibrium of the reactions of two phosphines (Ar3P), namely tri(1-naphthyl)phosphine and tri(o-tolyl)phosphine, are reported with reference electrophiles. The reason for the failure of the FLPs (A...

The ring-closing metathesis of N-(γ-fluoroallyl)-3-butenamides provides unsaturated fluoro δ-lactams in high yields, which are suitable synthetic intermediates of fluoro pseudopeptides.

The efficient sulfinate‐catalyzed intermolecular addition reaction of α‐substituted allenyl sulfones and allenoates with Michael acceptors is highlighted. The sequence proceeds under mild conditions to provide a scalable and efficient access to versatile functionalized alkynes, displaying a quaternary stereocentre at the propargylic position. This...

A novel and efficient method for the generation of phosphinoyl radicals from the combination of diphenyliodonium salt (Ph2I⁺,–OTf) with triethylamine (Et3N) in the presence of secondary phosphine oxides is reported. By employing this practical and simple approach, a large variety of 6-phosphorylated phenanthridines have been synthesized through the...

Starting from various arylphosphine oxides and symmetrically or unsymmetrically disubstituted alkynes the title synthesis has a broad substrate scope

This work describes the first visible-light mediated, metal-free hydrophosphinylation of unactivated alkenes with ethyl and butyl phosphinates. The reaction works with a low catalyst loading of 9-mesityl-10-methylacridinium perchlorate (Fukuzumi photocatalyst) (0.5 mol %) in the presence of diphenyliodonium triflate as an oxidant. The reaction proc...

A controlled degradation process enabling Natural Rubber (NR) depolymerization and using olefin metathesis reaction in ionic liquid medium is reported. Using trihexyl-(tetradecyl)phosphonium chloride (Cyphos101) and N,N-dioctylimidazolium bromide (C8C8ImBr), low-dispersity telechelic polymers are produced. With N,N-dioctylimidazolium bromide (C8C8I...

Bis-alkene substrates, containing one fluoroalkene and linked by an amide moiety, have been designed and synthesized to be subjected to ring-closing metathesis reactions. The substitution of fluoroalkene by a phenyl group enhanced the reactivity, and the resulting fluorinated lactams were obtained in high yields except when a hindered alkyl group w...

Upon simple activation with molecular oxygen at room temperature copper acetylides are shown to be convenient reagents for the alkynylation of sencondary phosphine oxides.

Encapsulation of ionic liquids (ILs) in crosslinked polyelectrolyte microcapsules, made via layer-by-layer assembly (LbL) was successfully conducted. Two different ILs were studied: 1-butyl-3-methylimidazolium tetrafluoroborate [Bmim]BF 4 and 1-butyl-3-methylimidazolium hexafluorophosphate [Bmim]PF 6. The polyelectrolyte microcapsules were successf...

Highly functionalized benzo[b]phosphole oxides were synthesized from reactions of arylphosphine oxides with alkynes under photocatalytic conditions by using eosin Y as the catalyst and tetrafluoroborate N-ethoxy-2-methylpyridinium as the oxidant. The reaction works under mild conditions and has a broad substrate scope. Mechanistic investigations ha...

Acyl chloride of N-phthaloyl-(S)-isoleucine is an efficient chiral auxiliary for the resolution of (+/-)-[2.2]paracyclophane-4-thiol. A preparative protocol, based on the conversion into diastereoisomeric thiolesters and separation by two fractional crystallizations and column chromatography, was developed. Deprotection with LiAlH4 allowed isolatio...

An efficient procedure for the synthesis of alkynylphosphine oxides based on the oxidative alkynylation of secondary phosphine oxides with copper acetylides was developed. Activation with molecular oxygen in the presence of either a mixture of 1,2-dimethylimidazole and triethylamine or N-methylimidazole alone enabled the formal umpolung of the poor...

meso-Bisalkynes and alkenes have potential as substrates for desymmetrization processes. The preparation of several meso-bis(1′-hydroxy-2′-propynyl)benzenes and their derivatives from phthalaldehydes using inexpensive and readily available reagents is described.

The present report describes an efficient and clean generation of sulfenate salts (R ¹ SO ⁻ ) by pyrolysis of readily available tert ‐butyl sulfoxides to give sulfenic acids (R ¹ SOH) and traceless isobutene, followed by hydrogen abstraction with a weak inorganic base (K 3 PO 4 ). The relevance of this process was exemplified through an in situ pal...

This chapter is dedicated to the main achievements since 2007 regarding the synthesis of BH3-phosphorus complexes. Among this class of compounds, phosphine-boranes are the most studied derivatives, mainly as valuable surrogates of phosphines, enabling easy handling and purification. In contrast, metal phosphido-boranes have so far only been conside...

Control of the surface chemistry and morphology of chalcogenide materials, which are highly polarizable, is a very interesting challenge as it might lead to breakthroughs in various fields such as electrochemistry, catalysis, and gas-phase separation. With this in mind, a new approach to synthesize structured Ge-based chalcogenide products has been...

Challenging homogeneous ring-closing metathesis reaction has been developed with reluctant fluorinated substrates. The combination of various parameters, such as the use of fluorinated aromatic solvent and appropriate substitution of the double bonds, allowed us to reach high levels of reactivity, leading to high yields of both new relevant five- a...

This is not breaking news: copper acetylides, readily available polymeric rock-stable solids, have been known for more than a century to be unreactive species and piteous nucleophiles. This lack of reactivity actually makes them ideal alkyne transfer reagents that can be easily activated under mild oxidizing conditions. When treated with molecular...

As part of our studies on copper-catalyzed arylation of nucleophiles, we report on Michaelis–Arbuzov reactions with a novel catalytic system, featuring a copper(I) salt as precatalyst without any additional ligand. This procedure is an interesting alternative to the use of expensive and toxic transition metals (nickel, palladium) traditionally used...

During the last two decades, metal-catalyzed reactions in nonconventional ionic liquid (IL) solvents has attracted increasing attention. Since the development of the olefin metathesis reaction, it has been pointed out that ruthenium catalysts are very efficient and have a large functional group tolerance, allowing their use in biologically active p...

A versatile synthesis of 1,2,3-triazolyl-4-phosphines from the borane complexes of phosphino-alkynes is reported. The efficiency of the procedure relies on the use of readily available silyl-protected alkynylphosphine-boranes, which were subjected to desilylation with TBAF followed by copper-catalyzed azide-alkyne-cycloaddition in one pot. Subseque...

Copper‐catalyzed CP cross‐coupling reactions between diphenylphosphine oxide and various 1‐bromo‐1,3‐butadienes readily provided a set of functionalized 1,3‐butadienyldiphenylphosphine oxides. Application of the latter to the synthesis of stereodefined 1,3‐butadienyldiphenylphosphines was successfully achieved via chemoselective reduction of their...

Original ruthenium supported ionic liquid phase (SILP) catalysts based on alginates as supports were developed for olefin metathesis reactions. The marine biopolymer, which fulfills most of the requisite properties for a support such as widespread abundance, insolubility in the majority of organic solvents, a high affinity for ionic liquids, high c...

This chapter describes procedures for the reduction of sulfur- and phosphorus-centered functional groups. It covers the most relevant advances in the field after the first edition of COS in 1991. The material has been organized on the basis of the nature of the substrate and the type of reducing agent, rather than on the mechanism of the process.Th...

The preparation of a series of new prochiral bis-alkynes is reported. A selection of chiral ligands is examined to gain additional information about the scope of the new asymmetric Huisgen click' reaction [the desymmetrisation of bis-alkynes using chiral ligands in conjunction with the widely applied copper-catalysed azide-alkyne cycloaddition (CuA...

Based on a previous study involving arenesulfenates, the enantioselective S-alkylation of benzyl and alkyl sulfenates R1SO− with alkyl halides, mediated by a cinchonidinium phase-transfer catalyst, was evaluated as a conceptually different synthetic approach to chiral sulfoxides. Direct application of our standard organocatalytic protocol, with met...

Copper-catalyzed P-arylation reactions have recently emerged as useful, cheaper, and less-toxic alternatives to the analogous palladium-catalyzed transformations. Since 2003, the combination of a set of ligands—mostly diamines and amino acids—with various copper salts has allowed the development of catalytic P-arylation reactions under rather mild...

The ligand exchange reaction between Au38(2-PET)24 (2-PET: 2-phenylethanethiolate) clusters and enantiopure planar chiral [2.2]paracyclophane-4-thiol 1 (PCP-4-SH) was studied using high performance liquid chromatography (HPLC) and mass spectrometry. It is shown that even at the initial stage of the reaction at least three out of the four symmetry-u...

An original and user-friendly synthesis of alkynylphosphine-boranes, useful building blocks in organic synthesis, based on an oxidative P-alkynylation reaction with readily available copper acetylides is reported. The ability of a secondary phosphine protected with a borane to undergo oxidative coupling without oxidation of the P-moiety is demonstr...

Iron(ic) phosphination: The iron-promoted hydrophosphination of alkenyl arenes with diphenylphosphine as phosphinating agent has been established. This method provides efficient access to diarylalkylphosphines. The regioselectivity of the reaction can be fine-tuned by the choice of the iron salts, offering highly selective access to both the β and...

Chitosan was used to immobilize phosphonium-based ionic liquids, combined with silica particles, to prepare catalytic materials in the form of highly porous monoliths. These catalytic materials were studied for the hydrogenation of 4-nitroaniline into p-phenylenediamine in the presence of formic acid as hydrogen donor in a column reactor. Experimen...

Dialkyl imidazoline, alkyl pyridine and alkyl quinoline containing salts have been synthesized and used as new surfactants for cationic exchange of layered silicates, such as montmorillonite (MMT) in order to evaluate their role in the formation of intercalated MMT clays. The new salts have been characterized by FTIR, 1H, 13C‐NMR spectra. These com...

Tetraalkylphosphonium ionic liquid (IL) was immobilized in a composite material made of alginate and cellulose fibers (to strengthen the gel) conditioned under the form of highly porous discs. These materials have been used for immobilizing Pd(II) by adsorption from HCl solutions. The metal reduction allows to prepare a catalytic material that was...

Alkynylphosphines or their borane complexes are available either through C–P bond forming reactions or through modification of the phosphorus or the alkynyl function of various alkynyl phosphorus derivatives. The latter strategy, and in particular the one involving phosphoryl reduction by alanes or silanes, is the method of choice for preparing pri...

New catalytic materials, based on palladium immobilized in ionic liquid supported on alginate, were elaborated. Alginate was associated with gelatin for the immobilization of ionic liquids (ILs) and the binding of palladium. These catalytic materials were designed in the form of highly porous monoliths (HPMs), in order to be used in a column reacto...

a] Keywords: Synthetic methods / Ring opening / Nitrogen heterocycles / Sulfur heterocycles / β-Amino thiols β-Amino thiols are an important class of bifunctional com-pounds that have found various applications in many areas of chemistry. This microreview highlights the synthetic methods

Copper-phosphido-borane complexes were synthesized and isolated for the first time. Their structures were experimentally and computationally investigated. They were shown to display catalytic activity in C(sp)-P bond formation.

Alginate was used for the immobilization of an alkylphospho- nium ionic liquid (IL). The IL-alginate resin served for Pd(II) bind- ing from HCl solutions. After chemical reduction of Pd(II), the composite was tested for the hydrogenation of nitrophenols (NPs) and 4-nitroaniline (4-NA) using sodium formate or formic acid as the hydrogen donor (HD) i...

Kinetic resolution of racemic 4-N,N-dimethylaminomethyl[2.2]paracyclophane with 50% sodium tetrachloropalladate and (R)-N-acetylphenylalanine under basic conditions resulted in the formation of a (S(p))-planar chiral palladacycle (35%, >99% ee). Similarly use of 100 mol% sodium tetrachloropalladate resulted in higher levels of conversion and recove...

A straightforward and gram scale synthesis (six-step synthesis from enantioenriched β-hydroxy esters) of new structurally simple phosphine–carbene ligands bearing a single stereogenic centre has been achieved. Enantioselectivities of up to 60–63% could be achieved in the hydrogenation of methylstilbene and dehydroaminoacids when the reactions were...

A new and smooth approach towards alkynylphosphine derivatives is described. It relies on the unprecedented catalytic coupling of secondary phosphine boranes with alkynyl bromides using the CuI/1,10-phenanthroline couple.

Introduction Synthesis of CILs CILs as reaction media and chiral reagents Miscellaneous applications Conclusion and prospects Acknowledgments References

Catalysts containing an ionic liquid phase immobilised on chitosan or alginate supports are successfully applied to the palladium catalysed allylation and amination reactions. The influence of the chemical structure of the support not only on the activity, but also on the recyclability and the reusability of the catalyst, is evaluated.

Preliminary results concerning a conceptually novel route to chiral sulfoxides based on the asymmetric alkylation of sulfenate salts with alkyl halides mediated by a chiral phase-transfer catalyst are described. As a representative example, o-anisyl methyl sulfoxide was produced in 96% yield and with an enantiomeric excess of 58% using commercial c...

Preliminary results on the mechanism of the asymmetricphosphination involving an achiral alkenyl triflate (cyclohexenyl triflate) and a secondary phosphane–borane, (methyl)phenylphosphane–borane (1) are reported. A catalytic cycle is proposed based on the variable-temperature 31P NMR characterization of the individual steps (oxidative addition, tra...

A catalytic system was designed in the form of highly porous monoliths (HPM) in order to be used in a continuous flow column reactor. This catalyst system was composed of an ionic liquid and a transition metal catalyst supported on a biopolymer matrix. Alginate was used as a natural support for immobilizing Cyphos IL-111 (an alkylphosphonium ionic...

A multinuclear NMR study shows that the deprotonation of diphenylphosphine-borane by n-BuLi in THF leads to a disolvated lithium phosphido-borane Ph(2)P(BH(3))Li of which Li(+) is connected to the hydrides on the boron and two THF molecules rather than to the phosphorus. This entity behaves as both a phosphination and a reducing agent, depending on...

Among numerous approaches for the asymmetric construction of chiral molecules, the use of chiral solvents was occulted for a long period. However, thanks to the recent apparition of ionic liquids, green solvents with unprecedented structural modularity, this particular approach in asymmetric synthesis is renewed.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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 is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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.

A new family of thiazoline ligands tethered to a sulfanyl or a sulfinyl group has been prepared using short and efficient reaction sequences. Among the different structures, one sulfanyl-thiazoline homopolymer was synthesized as a first example of an immobilized thiazoline ligand. The catalytic properties of these new ligands were evaluated in the...