Classical N-heterocyclic carbenes (NHCs), such as thiazolylidenes, 1,2,4-triazolylidenes, and imidazol(in)-2-ylidenes, are powerful organocatalysts for aldehyde transformations through the so-called Breslow intermediates (BIs). The reactions usually occur via electron-pair-transfer processes. In contrast, use of BIs in single-electron transfer (SET) pathways is still its infancy, scope limited by moderate reduction potential derived from classical NHCs (ca. −1.0 V versus standard calomel...

Ketones are among the most useful functional groups in organic synthesis, and they commonly encountered a broad range of compounds with various applications. Herein, we describe mesoionic carbene-catalyzed coupling reaction aldehydes non-activated secondary even primary alkyl halides. This metal-free method utilizes deprotonated Breslow intermediates derived from carbenes (MICs), which act as super electron donors induce single-electron reduction mild has substrate scope tolerates many...

Ketones, as essential functional group skeletons, have garnered significant interest due to their diverse transformations. Herein, we describe a versatile photoredox catalyzed deacylation-aroylation strategy that enables the direct transformation of alkyl ketones aryl ketones. This process involves deacylation dihydroquinazolinones derived from generate radicals, followed by subsequent NHC-catalyzed or NHC-mediated radical aroylation.

Mesoionic N-heterocyclic olefins have been developed, which feature high ylidic character. These compounds used as efficient catalysts for hydroboration of imines, nitriles, and N-heteroarenes.

N-Heterocyclic carbene (NHC)-catalyzed transformations through electron-pair-transfer processes have witnessed remarkable developments in the past decades, especially umpolung of aldehydes via Breslow intermediates (BIs). The role BIs single-electron transfer (SET) pathways has long been established biosynthesis, and last decade, it was extended to NHC organocatalysis. Here, we report that deprotonated mesoionic (BI - s) an astonishing small singlet/triplet (S/T) gap only 4.0 kcal/mol,...

N-heterocyclic carbene (NHC) organocatalysis has experienced significant advancements. Two distinct reaction pathways have been developed, ionic and radical, through Breslow intermediates (BIs) enolates (BI-s), respectively. The ability to selectively generate these is crucial for optimizing outcomes. In this paper we show that with mesoionic carbenes (MICs) it possible control the formation of BIs versus BI-s, use weak bases strong bases, Of particular interest coupling aldehydes alkyl...

Mesoionic carbene–iridium complex 1a has been investigated in the hydrogen isotope exchange (HIE) reaction of anilines. By employing 1 mol % as catalyst, anilines were selectively deuterated at ortho-position with high deuteration levels. High ortho-selectivity was observed for various competing directing groups, which is contrast catalytic results Kerr's catalysts.

The budding deuteriodifluoromethyl group (CF2D) is a potentially significant functional in medicinal chemistry. Herein, we investigated t-BuOK-catalyzed H/D exchange reaction of difluoromethylarenes DMSO-d6 solution. method provides excellent deuterium incorporation at the difluoromethyl group. Meanwhile, effect trace amount D2O solution on deuteration was also investigated.

Synthesis and coordination of 4-halo-1,2,3-triazolylidenes have been developed.

Paring a reductive reaction and an oxidative in one could be immensely important achieving atom economic environmental advantages. Herein, we report simple protocol that combines two such Heck reactions esterification by using mesoionic carbenes as catalysts to synthesize multiple valuable products under mild conditions.

Abstract This concept aims to summarize the direct coupling of aldehydes and organic halides (including activated unactivated halides) catalyzed by N ‐heterocyclic carbenes (NHCs). The key factor this transformation is formation Breslow intermediates, which are either nucleophilic or reductive. Additionally, activation inert C−H bond also was reviewed in performance via processes single electron transfer (SET) subsequent intramolecular 1, n ‐ hydrogen atom (HAT) intermolecular HAT. Finally,...

Ruthenium-catalyzed aromatic H/D exchange in [D4]acetic acid has been developed. By using N-heteroarenes as directing groups, both ortho and meta positions are selectively deuterated with high levels of D incorporation. Moreover, this strategy provides an alternative way to achieve meta-C-H activation.

Abstract Ketones are among the most useful functional groups in organic synthesis, and they commonly encountered a broad range of compounds with various applications. Herein, we describe mesoionic carbene‐catalyzed coupling reaction aldehydes non‐activated secondary even primary alkyl halides. This metal‐free method utilizes deprotonated Breslow intermediates derived from carbenes (MICs), which act as super electron donors induce single‐electron reduction mild has substrate scope tolerates...

The difluoromethyl group (CF2H) has received great attention due to its distinct properties in recent years. Herein, we report a new strategy for postmodification of compounds. Ortho-selective C-H borylation arenes is achieved by cyclometalated mesoionic carbene-Ir complex. regioselectivity controlled hydrogen bond between CF2H and the boryl via outer-sphere direction.

The mesoionic carbene-stabilized PS+ cation 6 has been synthesized and first characterized by single-crystal X-ray diffraction analysis. Computational investigations reveal the typical multiple-bond character of phosphorus–sulfur bond. A preliminary coordination investigation shows κ1 ligation with S atom bonded to Cu(I).

Hydrogen isotope exchange reactions of phenols and benzyl alcohols have been achieved by a mesoionic carbene-iridium catalyst with high ortho selectivity functional group tolerance. Control experiments indicated that acetate is crucial to realize the selectivity, whereas density theory calculations supported an outer-sphere direction hydrogen bonding between hydroxyl group.

Herein, we report the introduction of a silole unit into cycloparaphenylenes (CPPs), and two compounds [12]Si3CPP [16]Si4CPP are obtained by platinum- gold-mediated cyclooligomerization strategy. Their optical electronic properties studied UV–vis absorption fluorescence spectra, which show red shifts higher photoluminescence quantum yields (PLQYs) compared with corresponding CPPs.

N-Heterocyclic carbene adducts with main group elements (NHC=E) have aroused great interest and been widely investigated in coordination chemistry. Among them, N-heterocyclic chalcogens (NHC=Ch) known for a long time. Their investigations mostly focused on synthesis, chemistry electrochemistry. photophysical properties still remain unexplored. In this work, the of mesoionic sulfur selenium both solution solid state. These compounds showed blue fluorescence dichloromethane. While state,...

We describe an iridium-catalyzed ortho-selective C–H borylation of unprotected anilines. The employing strong σ-donating cyclometalated mesoionic carbene as C^C bidentate ligand is crucial for the high ortho-selectivity. Computational studies support outer-sphere X–H···Oboryl hydrogen bond interactions, which are strengthened by introduction. method shows broad substrate scope and functional group tolerance.

Abstract Activating dinitrogen under metal‐free conditions remains a significant challenge in chemistry. In this study, we computationally designed frustrated Lewis pair (FLP) system incorporating bis(trimethylsilyl)boryl substituent on mesoionic carbene (MIC) framework. Our models show both kinetic and thermodynamic favorability for activation. Aromaticity enhancement along the potential energy surface (PES) plays critical role driving reaction. This work provides insights into utilizing...

The synthesis of 4,5-diiodo-1,3-dimesityl-1,2,3-triazolium salts with different anions have been developed. These triazolium show diverse aggregation via halogen bonding between C–I bonds and anions. Triazolium halide exists as a tetramer saddle conformation. tetrafluoroborate trimer Chinese lantern shape trifluoroacetate acetate exist dimers, respectively, while the former shows boat conformation latter forms rectangle form linear polymer polyiodide.