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Single–carbon atom transfer reactions are lacking in organic synthesis, partly because of the absence of atomic carbon sources under standard solution-phase conditions. We report here that N-heterocyclic carbenes can serve as atomic carbon donors through the loss of a 1,2-diimine moiety. This strategy is applicable to single–carbon atom transfer to α,β-unsaturated amides, which can be converted into homologated γ-lactams through the formation of four single bonds to one carbon center in one operation.

We report herein on the phosphine-catalyzed Z-selective carbofluorination of alkynoates bearing an N-heteroarene unit, by using acyl fluorides as bifunctional reagents. This reaction proceeds through a pentacoordinate fluorophosphorane(V) intermediate, resulting in the formation of a C–F bond by a ligand coupling process. The Z-selectivity is attributed to the thermodynamic stabilization of a Z-isomer by orbital interactions between lone pair electrons of an N-heteroarene and the π* orbital of a carbonyl group.

Ito S., Fujimoto H., Tobisu M.. Non-Stabilized Vinyl Anion Equivalents from Styrenes by N-Heterocyclic Carbene Catalysis and Its Use in Catalytic Nucleophilic Aromatic Substitution. Journal of the American Chemical Society, 144, 15, 6714-6718, April 11, 2022. © 2022 American Chemical Society. https://doi.org/10.1021/jacs.2c02579., A protocol for the catalytic nucleophilic activation of unactivated styrenes is reported, which enables the generation of a non-stabilized alkenyl anion equivalent as a transient intermediate. In the reaction, N-heterocyclic carbenes add across styrenes to generate ylide intermediates, which can then be used in intramolecular nucleophilic aromatic substitution reactions of aryl fluorides, chlorides, and methyl ethers. The method allows for straightforward access to complex polyaromatic compounds.

C(aryl)-C(═O) bonds of aryl amides can be activated and added across alkenes with the aid of a nickel catalyst. This 1,2-carboaminocarbonylation reaction enables the dicarbofunctionalization of alkenes with an atom economy of 100%.

We report on C–C bond cleavage reactions of tropone derivatives by nickel catalysis. A single tropone derivative can be diversified into four different products with different ring skeletons by the judicious choice of the ligand.

Phenalenyl-based N,N-bidentate ligand-stabilized monovalent gallium(I) 1 was synthesized and characterized. Compound 1 promotes the oxidative addition of I-I, Si-Cl, C-I, and S-S bonds and oxidative cyclization with various Pi-components. Compound 1 can also coordinate to a tungsten complex to form a gallium-tungsten bond.

The palladium-catalyzed reaction of N-allylamides bearing a tethered nucleophile results in the extrusion of an amide moiety in the form of an isocyanate, with its subsequent capture by the pendant nucleophile­. This reaction involves the net catalytic transposition of an amide group.

We report herein the phosphine-catalyzed 1,2-diacylation of alkynes using acyl fluorides and acylsilanes as acyl sources. The key to the success of the reaction is a formal oxidative addition-ligand metathesis-reductive elimination cycle based on phosphine redox catalysis, which allows for the installation of two different acyl groups into an alkyne in a regioselective manner.

A monovalent (Non-Gomberg type) germanium radical 1 stabilized by phenalenyl-based bidentate ligand was synthe-sized. Because of the high thermal stability originating from spin delocalization over the phenalenyl moiety, it was possi-ble to isolate compound 1 in crystalline form by sublimation at ca. 300 °C. ESR spectra, crystallographic analysis, theo-retical calculations, and reactivities with carbon radicals suggest that the spin of 1 is distributed on the phenalenyl moie-ty, while 1 behaves as a germanium-centered radical in its reactions with C2Cl6, PhSSPh, and p-benzoquinone to form Ge−E (E = Cl, S, O) bonds.

C–F bonds of acyl fluorides can be cleaved and added across teth-ered alkenes in the presence of a cationic rhodium(I) tetrafluorobo-rate catalyst. This 1,2-carbofluorination reaction offers a powerful method for the synthesis of tertiary alkyl fluoride derivatives with atom economy of 100%. Mechanistic studies indicate that the concerted action of a rhodium cation and a tetrafluoroborate anion is the key for the success of this catalytic cleavage and formation of C–F bonds in a controlled manner.

The catalytic ortho to para transposition of a silyl group in aniline derivatives is described. [RuCl2(p-cymene)]2/BINAP in conjunction with a Cu(OAc)2 additive serves as a potent catalytic system. This method is also applicable to the isomerization of 2-silylpyrrole derivatives to the corresponding 3-silyl isomers.

We report herein that nickel-catalyzed reaction of aryl imidates bearing an N-benzyl group results in 1,4-migration of an O-aryl group via the cleavage of C–O and C–H bonds.

The syntheses of rhodium, iridium, and iron π complexes bearing 4,5-benzotropone ligands are reported. X-ray crystallographic analyses revealed that a tropone core coordinates to a metal center in a η4 manner with a tub-form geometry. Some of the benzotropone π complexes exhibited catalytic activity for N-alkylation of aniline by borrowing hydrogen.

The nickel-catalyzed cross-coupling of methoxyarenes was applied to buflavine, which allows for the selective monosubstitution of one of the two methoxy groups in the molecule, leading to the formation of 2- and 3-substituted isomers. Trimethylsilylmethyl (TMSCH2), phenyl, and alkynyl groups can be introduced into buflavine using this method. The resulting TMSCH2 analogue of buflavine can also be converted into several other derivatives.

We report on the N-heterocyclic carbene (NHC)-catalyzed Truce-Smiles rearrangement of aniline derivatives, in which an unactivated C(aryl)-N bond is cleaved, leading to the formation of a new C(aryl)-C bond. The key to the success of this reaction is the utilization of a highly nucleophilic NHC, which enables the formation of a highly nucleophilic ylide intermediate that is generated from an α,β-unsaturated amide.

Carbon dioxide is regarded as a reliable C1 building block in organic synthesis because of the nontoxic, abundant, and economical characteristics of carbon dioxide. In this manuscript, a commercially available oxovanadium(v) compound was demonstrated to serve as an efficient catalyst for the catalytic amination of carbon dioxide under ambient pressure in the synthesis of ureas. The catalytic transformation of chiral amines into the corresponding chiral ureas without loss of chirality was also performed. Furthermore, a gram-scale catalytic urea synthesis under ambient pressure was successfully achieved to validate the scalability of this catalytic activation of carbon dioxide.

We report herein that nickel-catalyzed reaction of aryl imidates bearing an N-benzyl group results in 1,4-migration of an O-aryl group via the cleavage of C–O and C–H bonds. This protocol allows for the benzylic C–H bond arylation of benzylamine building blocks using phenols as an aryl source to form elaborate diarylmethylamine derivatives.

A dicationic photoredox catalyst composed of phenylene-bridged bis(benzimidazolium) (BBIm2+) was designed, synthesised and demonstrated to promote the photochemical decarboxylative hydroxylation and dimerisation of carboxylic acids. The catalytic activity of BBIm2+ was higher than that for a monocation analogue, suggesting that the dicationic nature of BBIm2+ plays a key role in these decarboxylative reactions. The rate constant for the decay of the triplet–triplet absorption of the excited BBIm2+ increased with increasing concentration of the carboxylate anion with a saturated dependence, suggesting that photoinduced electron transfer occurs within the ion pair complex composed of the triplet excited state of BBIm2+ and a carboxylate anion., A new organic dication, phenylene-bridged bis(benzimidazolium), catalyses the photochemical decarboxylative hydroxylation and dimerisation of carboxylic acids.

The palladium-catalyzed synthesis of diarylborinic acid derivatives by intermolecular cross-coupling between aryl iodides and (amino)dihydrideborane is reported. The key to success of the reaction ...

Nickel-catalyzed decarbonylation of acylsilanes is developed. In sharp contrast to cross-coupling reactions of acylsilanes, in which the silyl group serves as a leaving group, the silyl group is retained in the product in this decarbonylation reaction. Although the strong binding of the dissociated CO to the nickel center frequently hinders catalyst turnover in nickel-mediated decarbonylative reactions, this reaction can be catalyzed by nickel complexes bearing a CO ligand.

We report on a method for the synthesis of fluorinated dibenzophospholes using triarylphosphine via dearylative annulation with an aryne. This intermolecular annulation allows the preparation of a variety of fluorinated dibenzophospholes from simple building blocks. The key to the success of this dearylative annulation is the formation of a five-coordinated tetraarylfluorophosphorane. In this work, we successfully synthesized stable tetraarylfluorophosphorane, the structure of which was unambiguously determined by X-ray crystallography.

The oxovanadium(V)-catalyzed oxidative cross-coupling of enolates using O2 as a terminal oxidant is reported, where a boron enolate and a silyl enol ether were employed as enolates. The redox behavior of V(V/IV) in this reaction under O2 was investigated by ESR and 51V NMR experiments.

We have developed a palladium-catalyzed addition of a C-Si bond of acylsilanes across a range of unactivated allenes. The reaction proceeds with complete regioselectivity, in which a silyl group binds to the central carbon of the allene, allowing for the straightforward access to functionalized alkenylsilane derivatives.

Currently, catalytically transferable carbenes are limited to electron-deficient and neutral derivatives, and electron-rich carbenes bearing an alkoxy group (i.e., Fischer-type carbenes) cannot be used in catalytic cyclopropanation because of the lack of appropriate carbene precursors. We report herein that acylsilanes can serve as a source of electron-rich carbenes under palladium catalysis, enabling cyclopropanation of a range of alkenes. This reactivity profile is in sharp contrast to that of metal-free siloxycarbenes, which are unreactive toward normal alkenes. The resulting siloxycyclopropanes serve as valuable homoenolate equivalents, allowing rapid access to elaborate β-functionalized ketones.

Decarbonylative cyanation of acyl fluorides can be catalyzed by a Pd/Xantphos system. This protocol is also applicable to the conversion of acyl chlorides.

Although sufficient tolerance against attack by superoxide radicals (O

The properties of 1-hydroxy-4,5-arene-fused tropyliums were assessed based on experimental and theoretical investigations. An X-ray crystallographic analysis revealed a decrease of bond alternation in the seven-membered ring of 1-hydroxy-4,5-benzotropylium derivatives compared with that of the parent 4,5-benzotropones, which is indicative of an increase in aromaticity upon protonation. NICS and AICD calculations also supported the increased aromaticity of 1-hydroxy-4,5-arene-fused tropylium. The pKa values for a series of 1-hydroxy-4,5-arene-fused tropylium derivatives were also determined.

Catalysis by late transition metal complexes is enabled by their facile reversible redox reactivity based on their partially filled d-orbitals. The realization of such redox catalysis by p-block elements is a challenging but rewarding research subject for the advancement in both fundamental main group chemistry and sustainable catalytic technology. In this context, a P(III)/P(V) redox cycle that involves pentacoordinate phosphorane is a competent manifold for applications to catalytic reactions via a formal oxidative addition/transmetalation/reductive elimination sequence. Despite the promising stoichiometric redox reactivity of pentacoordinate organophosphorus compounds, their use in catalytic processes have been primarily limited to oxygen transfer reactions that involve the interconversion between phosphines and phosphine oxides, except for relatively simple, prototypical transformation, such as hydrogenationand reduction of allyl bromides. We report herein on the phosphine-catalyzed hydrovinylation reaction by three-component coupling of acyl fluorides, silyl enol ethers, and alkynoates. The key to the success of the reaction is the formal transmetalation between pentacoordinate P(V) species (i.e., fluorophosphorane) and a silyl enol ether, which allows for C–C bond formation between the polarity-mismatched sites. The bond formation that cannot be attained even by transition metal catalysis is accomplished by a P(III)/P(V) manifold.

The catalytic

Correction for ‘Nickel-catalyzed 1,4-aryl rearrangement of aryl N-benzylimidates via C–O and C–H bond cleavage’ by Satoshi Ogawa et al., Chem. Commun., 2022, 58, 7909–7911, https://doi.org/10.1039/D2CC02355E.

An S-shaped p-oligophenyl derivative was synthesized, as exemplified by linear [3]spirobifluorenylene (R,P,R/S,M,S)-1, which consisted of two p-sexiphenyls tied at the spiro-carbons of three spirob...