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A palladium‐catalyzed highly C−S‐selective Stille cross‐coupling between aryl thianthrenium salts and tri‐ or tetrasubstituted alkenyl stannanes is described. Herein, critical challenges including site‐ and chemoselectivity control are well addressed through C−H thianthrenation and C−S alkenylation, thereby providing an expedient access to stereodefined tri‐ and tetrasubstituted alkenes in a stereoretentive fashion. Indeed, the palladium‐catalyzed Stille‐alkenylation of poly(pseudo)halogenated arenes displays privileged capability to differentiate C−S over C−I, C−Br, C−Cl bonds, as well as oxygen‐based triflates (C−OTf), tosylates (C−OTs), carbamates and sulfamates under mild reaction conditions. Sequential and multiple cross‐couplings via selective C−X functionalization should be widely applicable for increasing functional molecular complexity. Modular installation of stereospecific alkene motifs into pharmaceuticals illustrated the synthetic application of the present protocol in drug discovery. [ABSTRACT FROM AUTHOR]

Comprehensive Summary Conjugate addition and allylic substitution are two essential chemical transformations, and they could be competitive for substrates with multiple reactive sites. Herein, we report the diversified enantioselective synthesis of cyclobutenes via the functionalization of cyclobutenones. The conjugate addition of cyclobutenones with arylzinc halides provided enantioenriched cyclobutenes with all‐carbon quaternary centers. On the other hand, when cyclobutenones with gem‐dichloro groups were employed, a chemo‐ and enantioselective allylic substitution occurred. Further synthetic utility was demonstrated for synthesizing versatile cyclobutane derivatives, together with ring‐opening and expansion products. [ABSTRACT FROM AUTHOR]

Spiro-heterocycles have attracted significant interest due to their unique biological properties with fewer side effects compared to traditional drugs. Herein, a novel method is reported for the synthesis of a series of spiro-heterocycles possessing a quinoline motif. The strategy utilizes rhodanine derivatives, hydrazonoyl chlorides, and 2-chloroquinoline-3-carbaldehyde, and proceeds via a one-pot sequential pseudo-five-component reaction. The reactions are found to proceed in a regioselective and chemoselective manner. [ABSTRACT FROM AUTHOR]

A chemo- and regioselective hydroarylation of vinylsilanes with (hetero)aryl iodides under Ni–H catalysis is reported. This mild and straightforward protocol furnishes the anti-Markovnikov products in good yields as single regioisomers. This study demonstrates excellent control over the chemoselectivity and complements existing methods for the construction of homobenzylic silanes. [ABSTRACT FROM AUTHOR]

Despite the broad potential applications of C-glycosides, facile synthetic methods remain scarce. Transforming glycosyltransferases with promiscuous or natural O-specific chemoselectivity to C-glycosyltransferases is challenging. Here, we employ rational directed evolution of the glycosyltransferase MiCGT to generate MiCGT-QDP and MiCGT-ATD mutants which either enhance C-glycosylation or switch to O-glycosylation, respectively. Structural analysis and computational simulations reveal that substrate binding mode govern C-/O-glycosylation selectivity. Notably, directed evolution and mechanism analysis pinpoint the crucial residues dictating the binding mode, enabling the rational design of four enzymes with superior non-inherent chemoselectivity, despite limited sequence homology. Moreover, our best mutants undergo testing with 34 substrates, demonstrating superb chemoselectivities, regioselectivities, and activities. Remarkably, three C-glycosides and an O-glycoside are produced on a gram scale, demonstrating practical utility. This work establishes a highly selective platform for diverse glycosides, and offers a practical strategy for creating various types of glycosylation platforms to access pharmaceutically and medicinally interesting products. Despite the potential utility of C-glycosides, synthetic routes for their synthesis are limited. Here, the authors used rational directed evolution of the glycosyltransferase MiCGT to generate MiCGT-QDP and MiCGT-ATD mutants which either enhance C-glycosylation or switch to O-glycosylation, respectively, and reveal the substrate binding mode that governs C-/O-glycosylation selectivity. [ABSTRACT FROM AUTHOR]

Despite the existence of three competing reactions for propargyloxyoxindoles, we report a chemoselectivity switch between enantioselective propargyl [2,3]‐Wittig rearrangement and Conia‐ene‐type reactions, with suppression of the [1,2]‐Wittig‐type rearrangement. Using C1‐symmetric imidazolidine‐pyrroloimidazolone pyridine as the ligand and Ni(acac)2 as the Lewis acid, diverse 3‐hydroxy 3‐substituted oxindoles containing allenyl groups were obtained in up to 98 % yield and 99 % ee via asymmetric propargyl [2,3]‐Wittig rearrangement. In the presence of AgOTf‐Duanphos, chiral spiro dihydrofuran oxindoles were given in up to 98 % yield and 91 % ee through a Conia‐ene‐type reaction. [ABSTRACT FROM AUTHOR]

A nickel-catalyzed synthesis of hydrazoarenes utilizing NH3BH3 in water has been developed. This simple synthesis, facilitated by a nickel catalyst, exhibits excellent chemoselectivity, with 22 examples provided without the need for any column chromatography. This strategy introduces a novel nickel-catalyzed reduction system in water, holding promise for industrial applications. [ABSTRACT FROM AUTHOR]

Comprehensive Summary Enhancing the DNA toolbox with innovative photochemical reactions is pivotal for advancing nucleic acid‐based technologies. Aldehyde groups, versatile bioorthogonal handles for imine formation under acidic conditions, are particularly valuable due to their roles in nucleic acid epigenetics. Here, we present the first photocatalytic on‐DNA aldehyde allylation, enabling precise DNA functionalization under mild, neutral aqueous conditions. Our approach utilizes a photocatalytic polarity‐reversal reaction between DNA‐conjugated benzaldehydes and allyl sulfones. This reaction demonstrates exceptional chemoselectivity while preserving DNA integrity. By varying allyl sulfones, we achieve site‐specific labeling of non‐native DNA with the aldehyde group and cross‐linking with DNA‐bearing allyl sulfones. Furthermore, our method facilitates selective labeling and pull‐down enrichment of 5‐formylpyrimidine nucleotides among complex cellular DNA. This photocatalytic on‐DNA aldehyde transformation expands the limited bioorthogonal photochemical toolboxes, providing novel avenues for functionalizing both non‐native and native aldehyde modifications on DNA. [ABSTRACT FROM AUTHOR]

The development of all kinds of covalent drugs had a major impact on the improvement of the human health system. Covalent binding to target proteins is achieved by so‐called electrophilic warheads, which are incorporated in the respective drug molecule. In the last decade, specifically acrylamides emerged as attractive warheads in covalent drug design. Herein, a straightforward palladium‐catalyzed hydroaminocarbonylation of acetylene has been developed, allowing a modular and diverse synthesis of bio‐active acrylamides. This general protocol features high atom efficiency, wide functional group compatibility, high chemoselectivity and proceeds additive free under mild reaction conditions. The synthetic utility of this protocol is showcased in the synthesis of ibrutinib, osimertinib, and other bio‐active compound derivatives. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: 2,3‐Allenyl amines have shown wide applicability in biomedical and synthetic applications. Due to their enormous potential for applications, researchers have been dedicated to the development of methods for synthesizing 2,3‐allenyl amines. Herein, a palladium‐catalyzed three‐component reaction of 2‐alkynyl‐1,4‐diol dicarbonates, organoboronic acids, and nitrogen nucleophiles forming 2,3‐allenyl amines with excellent regio‐ and chemo‐selectivity has been developed. Substrate compatibility and synthetic applications have been demonstrated. Control experiments supported a mechanism involving 1,2,3‐triene‐Pd species and methylene‐π‐allyl palladium species. [ABSTRACT FROM AUTHOR]

Comprehensive Summary Ketenimine zwitterionic salt (KZS), a novel and stable ketenimine precursor, is still underexplored in the realm of chemical synthesis. In this study, we demonstrate the transformation of pyrrole derivatives through the cyclization of KZS with α‐aminoketones. The diastereoselectivity of this reaction is influenced by the solvent, enabling the isolation of 3‐hydroxypyrrolidine diastereomers with the highest reported dr value of 21 : 1. Furthermore, the chemoselectivity is modulated by the choice of base, yielding 2‐aminopyrrole derivatives as the major products. This research offers a sustainable approach to harnessing the potential of KZS in organic synthesis, contributing to a greener chemical process. [ABSTRACT FROM AUTHOR]

Lipopeptides are an important class of biomolecules for drug development. Compared with conventional acylation, a chemoselective lipidation strategy offers a more efficient strategy for late‐stage structural derivatisation of a peptide scaffold. It provides access to chemically diverse compounds possessing intriguing and non‐native moieties. Utilising an allenamide, we report the first semisynthesis of antimicrobial lipopeptides leveraging a highly efficient thia‐Michael addition of chemically diverse lipophilic thiols. Using chemoenzymatically prepared polymyxin B nonapeptide (PMBN) as a model scaffold, an optimised allenamide‐mediated thia‐Michael addition effected rapid and near quantitative lipidation, affording vinyl sulfide‐linked lipopeptide derivatives. Harnessing the utility of this new methodology, 22 lipophilic thiols of unprecedented chemical diversity were introduced to the PMBN framework. These included alkyl thiols, substituted aromatic thiols, heterocyclic thiols and those bearing additional functional groups (e.g. amines), ultimately yielding analogues with potent Gram‐negative antimicrobial activity and substantially attenuated nephrotoxicity. Furthermore, we report facile routes to transform the allenamide into a β‐keto amide on unprotected peptides, offering a powerful "jack‐of‐all‐trades" synthetic intermediate to enable further peptide modification. [ABSTRACT FROM AUTHOR]

We disclose herein our evaluation of competitive (hetero)aryl‐X (X: Br>Cl>OTf) reactivity preferences in bisphosphine/Ni‐catalyzed C−N cross‐coupling catalysis, using furfurylamine as a prototypical nucleophile, and employing DalPhos and DPPF as representative ancillary ligands with established efficacy. Beyond this general (pseudo)halide ranking, other intriguing structure‐reactivity trends were noted experimentally, including the unexpected observation that bulky alkyl (e. g., R=tBu) substitution in para‐R‐aryl‐X electrophiles strongly discourages (pseudo)halide reactivity relative to smaller substituents (e. g., nBu, Et, Me), despite being both remote from, and having a similar electronic influence on, the reacting C−X bond; such effects on nickel oxidative addition have not been documented previously and were not observed in our comparator reactions presented herein involving palladium. Density functional theory modeling of such PhPAd‐DalPhos/Ni‐catalyzed C−N cross‐couplings revealed the origins of competitive turnover of C−Br over C−Cl, and possible ways in which bulky para‐alkyl substitution might discourage net electrophile uptake/turnover, leading to inversion of halide selectivity. [ABSTRACT FROM AUTHOR]

Substrate-controlled divergent reactions of between salicylaldehydes and acrylates have been developed. By using methyl acrylate as the substrate with salicylaldehydes, a domino reaction was established, delivering coumarins with good yield (up to 81% yields) and high chemoselectivity under mild conditions. Whereas the methyl acrylate was changed to tert-butyl acrylate or iso-propyl acrylate, the classical Morita − Baylis − Hillman adducts were produced in good yields (up to 75% yields) under near exclusivity under the otherwise identical reaction conditions, without any other competitive products. Additionally, the synthetic utility of the present methodology was further demonstrated by synthetic transformation. The structure of the typical product was unambiguously established by single crystal X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Transition‐metal‐catalyzed asymmetric alkylation of aldehydes represents a straightforward strategy for the synthesis of chiral secondary alcohols. However, efficient methods using organoborons as coupling reagents are rare. Herein, we report a highly enantioselective nickel‐catalyzed alkylation reaction of aldehydes, using readily available alkylborons as nucleophiles. A wide variety of chiral secondary alcohols were prepared from commercially available aldehydes with high yields. The key to the excellent enantioselectivity and chemoselectivity was the employment of a bulky C2‐symmetric chiral NHC ligand. This protocol features excellent enantiocontrol, mild conditions, and good functional group compatibility. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Transition‐metal‐catalyzed asymmetric alkylation of aldehydes represents a straightforward strategy for the synthesis of chiral secondary alcohols. However, efficient methods using organoborons as coupling reagents are rare. Herein, we report a highly enantioselective nickel‐catalyzed alkylation reaction of aldehydes, using readily available alkylborons as nucleophiles. A wide variety of chiral secondary alcohols were prepared from commercially available aldehydes with high yields. The key to the excellent enantioselectivity and chemoselectivity was the employment of a bulky C2‐symmetric chiral NHC ligand. This protocol features excellent enantiocontrol, mild conditions, and good functional group compatibility. [ABSTRACT FROM AUTHOR]

Pyridazine is a significant skeleton that widely exists in drugs and bioactive molecules. We herein describe expeditious approaches to access polysubstituted pyridazines from readily accessible unactivated ketones and acylhydrazones via Cu-promoted C(sp3)–C(sp3) coupling/cyclization sequences in a single-step fashion. Notably, the disparate 3,4,6-trisubstituted pyridazines and 3,5-disubstituted pyridazines could be obtained by tailoring the ketone's structure and reaction conditions. These transformations feature good functional group compatibility, excellent step-economy, and chemoselectivity. The potential synthetic utility of these conversions is illustrated by scale-up reactions and late-stage derivatizations of the as-prepared pyridazine products. [ABSTRACT FROM AUTHOR]

Decomposition of aryl and unsubstituted diazo ester into Rh(II)‐carbenes by the [(IMes)Rh2(OAc)4] complex is shown to be slower than with Rh2(OAc)4. Diazo esters substituted by a second electron‐withdrawing group do not suffer nitrogen extrusion when exposed for several hours to this (NHC)Rh(II) complex at room temperature. This chemoselective decomposition of diazo esters depending on their substituent (Ar, H, EWG) can furthermore be achieved on a mixture of substrates. The catalytic activity of [(IMes)Rh2(OAc)4] towards electron‐poor diazo compounds is also restored by heating to reflux in chloroform, or after decomplexation of the NHC by addition of GaCl3. The [(IMes)Rh2(OAc)4] complex was then used to induce a fully selective reaction cascade from a mixture of two diazo esters. First, a donor/acceptor diazo compound was decomposed selectively at room temperature to give an intermolecular O−H insertion product without any decomposition of the electron poor diazo compound. Addition of GaGl3 then triggered nitrogen extrusion from the diazo malonate to give a 1,5‐C−H insertion product. This transformation, where decomposition of diazo compounds catalyzed by Rh(II) complexes can be externally controlled, represents the first example of assisted tandem catalysis with two metal carbene precursors. [ABSTRACT FROM AUTHOR]

A tetrasaccharide repeating unit of the O‐antigen from Escherichia coli O33 has been synthesized for the first time using a chemoselective [1+1+2] one‐pot glycan assembly strategy. The phosphoglycerol moiety was installed by using the phosphoramidite method with benzylidene‐protected glycerol 2‐phosphoramidite as the reagent. Overall, the target tetrasaccharide was synthesized from monosaccharide building blocks in 12 linear steps, resulting in a satisfactory yield of 28 %. [ABSTRACT FROM AUTHOR]

Bis(alkenyl)boronates react with optically active Ir(π‐allyl) species in a process that involves allylation of the more substituted olefin and 1,2‐metalate shift of the less substituted olefin. The method constructs valuable enantioenriched tertiary allylic boronic esters with high chemoselectivity, enantioselectivity and diastereoselectivity. Allylic functionalization reactions transform the 1,3‐stereodiad to 1,5‐ and 1,6‐stereochemical relationships. [ABSTRACT FROM AUTHOR]

This article presents an efficient one-step synthesis of tetrahydropyrazolo[1,5- a ]pyrimidines through the recyclization of N -arylitaconimides with aminopyrazoles. The heterocyclic system of pyrazolo[3,4- b ]pyrimidine is known for its diverse biological properties, making its derivatives significant in pharmaceutical and medicinal chemistry. The study focuses on the regio- and chemoselective cascade reaction of N -arylitaconimides with 5-aminopyrazoles, demonstrating a new approach to synthesizing pyrazolo[1,5- a ]pyrimidines and pyrazolo[3,4- b ]pyridines. The methodology, involving boiling in isopropyl alcohol with acetic acid, yields selectively either pyrazolo[3,4- b ]pyridines or pyrazolo[1,5- a ]pyrimidines based on the substituents in the aminopyrazoles. The study elucidates the reaction mechanism, structural characterization using NMR spectroscopy, and confirms the structures via high-performance liquid chromatography and mass spectrometry. The simplicity and synthetic potential of this approach make it a valuable method for the preparation of these heterocyclic frameworks. [ABSTRACT FROM AUTHOR]

A series of new aromatic substituted indanone and indanol building blocks have been prepared and are anticipated to aid future drug discovery studies. In total, seven compounds (7, 12–17) are expounded on, and all have been fully characterized. In doing so, we have shown multiple examples of highly chemoselective reactions. One example employed an adaptation of Fujioka's chemoselective reduction methodology, allowing an ester to be reduced in the presence of a ketone. In another example, an uncommon benzylic methyl group to aldehyde oxidation was demonstrated for two different compounds. These and other chemoselective interconversions allowed us to identify compound (12) as a remarkably flexible springboard for accessing a diverse array of indan-based building blocks (13–17). [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Optically active phthalides are prevalent in many natural and bioactive products. Herein, a novel dynamic kinetic resolution of isobenzofuranone derivatives through palladium‐catalyzed asymmetric allylic alkylation has been developed to synthesize phthalide derivatives bearing vicinal quaternary and tertiary stereocenters with high yields, showing excellent chemo‐, enantio‐ and diastereoselectivity. Furthermore, gram‐scale experiment underwent smoothly and the transformation of product could build a bridged bicyclic skeleton. [ABSTRACT FROM AUTHOR]

A series of new aromatic substituted indanone and indanol building blocks have been prepared and are anticipated to aid future drug discovery studies. In total, seven compounds (7, 12–17) are expounded on, and all have been fully characterized. In doing so, we have shown multiple examples of highly chemoselective reactions. One example employed an adaptation of Fujioka’s chemoselective reduction methodology, allowing an ester to be reduced in the presence of a ketone. In another example, an uncommon benzylic methyl group to aldehyde oxidation was demonstrated for two different compounds. These and other chemoselective interconversions allowed us to identify compound (12) as a remarkably flexible springboard for accessing a diverse array of indan-based building blocks (13–17).

The chemoselective [4+2] annulation/aromatization reactions between benzofuran‐derived azadienes and N−Ts cyanamides are developed, affording a convenient method for synthesizing benzofuro[3,2‐d]pyrimidin‐2‐amines under mild conditions. Herein, N−Ts cyanamides participated in reactions selectively via carbodiimide anion intermediates and the corresponding cyanamide anion intermediates derived products were not observed. The proposed chemoselective stepwise reaction mechanism was well supported by DFT calculations. [ABSTRACT FROM AUTHOR]

The electrochemical stereoselective dehydrogenative homocoupling of β‐naphthylamine derivatives was investigated and successfully accomplished, the chiral diaryl amines being obtained in up to 60 % yield. The use of an enantiopure β‐naphthylamine featuring an aminoalcohol as chiral auxiliary led to the expected 2,2'‐binaphthyl diamine derivative in up to 96/4 diastereoisomeric ratio. The application of the methodology to the intramolecular cross coupling of the enantiopure bis‐N‐β‐naphthylamine 1,2‐trans‐diamino cyclohexane led to the formation of a single enantiopure diastereoisomer in 37 % yield. [ABSTRACT FROM AUTHOR]

In this study, a novel approach for the tertiary α‐alkylation of ketones using alkanes with electron‐deficient C─H bonds is presented, employing a synergistic catalytic system combining inexpensive copper salts with aminocatalysis. This methodology addresses the limitations of traditional alkylation methods, such as the need for strong metallic bases, regioselectivity issues, and the risk of over alkylation, by providing a high reactivity and chemoselectivity without the necessity for pre‐functionalized substrates. The dual catalytic strategy enables the direct functionalization of C(sp3)─H bonds, demonstrating remarkable selectivity in the presence of conventional C(sp3)─H bonds that are adjacent to heteroatoms or π systems, which are typically susceptible to single‐electron transfer processes. The findings contribute to the advancement of alkylation techniques, offering a practical and efficient route for the construction of C(sp3)─C(sp3) bonds, and paving the way for further developments in the synthesis of complex organic molecules. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Although various routes have been reported for haloazidation, unavoidable problems exist, such as environmentally unfriendly monomer halogen, the need for in situ generation of unstable halogen azides (XN3), applicability to one type of haloazidation and inability to precisely control selectivity. Herein, we developed a universal strategy for haloazidation of alkenes through controlling the reactivity of IBA‐N3 by switching halogen salts, allowing for the synthesis of a diversity of halogen azide products. Mechanistic studies have shown that by tuning the reactivity of IBA‐N3 via switching halogen salts, different intermediates can be controllably produced to achieve regioselectivity and chemoselectivity in the haloazidation of alkenes. [ABSTRACT FROM AUTHOR]

Molecular modifications have been practiced for more than a century and nowadays they are widely applied in food, pharmaceutical, or other industries to manipulate the physicochemical, bioactivity, metabolic/catabolic, and pharmacokinetic properties. Among various structural modifications, the esterification/O-acylation has been well-established in altering lipophilicity and bioactivity of parent bioactive compounds, especially natural polyphenolics, while maintaining their high biocompatibility. Meanwhile, various classic chemical and enzymatic protocols and other recently emerged cell factory technology are being employed as viable esterification strategies. In this contribution, the main motivations of phenolic esterification, including the tendency to replace synthetic alkyl phenolics with safer alternatives in the food industry to improve the bioavailability of phenolics as dietary supplements/pharmaceuticals, are discussed. In addition, the toxicity, metabolism, and commercial application of synthetic and natural phenolics are briefly introduced. Under these contexts, the mechanisms and reaction features of several most prevalent chemical and enzymatic esterification pathways are demonstrated. In addition, insights into the studies of esterification modification of natural phenolic compounds and specific pros/cons of various reaction systems with regard to their practical application are provided. [ABSTRACT FROM AUTHOR]

Cobalt complexes featuring triazine‐based PNP ligands have proven to be exceptionally active and chemoselective pre‐catalysts in facilitating the dehydrogenative coupling between silanes and amines, leading to the synthesis of diverse aminosilanes. Notably, even challenging substrates exhibited high reactivity. The catalyst's unique feature of avoiding coupling with tertiary silanes enhances process chemoselectivity. It facilitates a more precise synthesis of silylamines possessing of SiH2−N and SiH−N motifs, overcoming challenges associated with broader reactivity seen in previous systems. In terms of its remarkable chemoselectivity, it is also noteworthy that the catalytic system exhibits both versatility and efficacy in converting substrates with untouched double and triple carbon‐carbon bonds. This accomplishment is particularly significant, given previous challenges brought about by the activity of commonly employed catalysts in the competitive hydrosilylation process. [ABSTRACT FROM AUTHOR]

Late-stage specific and selective diversifications of peptides and proteins performed at target residues under ambient conditions are recognized to be the most facile route to various and abundant conjugates. Herein, we report an orthogonal modification of cysteine residues using alkyl thianthreium salts, which proceeds with excellent chemoselectivity and compatibility under mild conditions, introducing a diverse array of functional structures. Crucially, multifaceted bioconjugation is achieved through clickable handles to incorporate structurally diverse functional molecules. This "two steps, one pot" bioconjugation method is successfully applied to label bovine serum albumin. Therefore, our technique is a versatile and powerful tool for late-stage orthogonal bioconjugation. Late-stage specific and selective modifications of peptides and proteins at target residues under ambient conditions are the most facile routes to various bioconjugates. Here, the authors report an orthogonal modification of cysteine residues using alkyl thianthreium salts, which proceeds with excellent chemoselectivity and compatibility under mild conditions, introducing a diverse array of functional structures. [ABSTRACT FROM AUTHOR]

Metal-free, photoredox-catalyzed aromatization-driven deconstructive functionalization of spiro-dihydroquinazolinones with α-CF3 alkenes is presented. The readily available spiro-dihydroquinazolinones reacted efficiently with α-CF3 alkenes during photocatalysis to give the gem-difluoroallylated and the CF3-containing quinazolin-4(3H)-ones in good yields with excellent chemoselectivity. The selectivity depends on the electron effect of substituents in α-CF3 alkenes. A wide range of four-, five-, six-, seven-, eight- and twelve-membered spiro-dihydroquinazolinones were compatible with this transformation. The protocol is also characterized by the mild and redox-neutral reaction conditions, good functional group compatibility and excellent atom economy. Mechanistic studies revealed that the reaction proceeds via a radical pathway. [ABSTRACT FROM AUTHOR]

Herein, we report a general copper‐catalyzed method for the tunable oxygenative rearrangement of tetrahydrocarbazoles to cyclopentyl‐bearing spiroindolin‐2‐ones and spiroindolin‐3‐ones. The method demonstrates excellent chemoselectivity, regioselectivity, and product control simply by using the H2O and O2 as oxygen source, respectively. This open‐flask method is safe and simple to operate, and no other chemical oxidants are required. Besides, inspired from the unique pathway of 1, 2‐migration rearrangement, a highly controllable hydroxylation of indoles for the construction of C3a‐hydroxyl iminium indolines was also developed. Mechanistic experiments suggest that a single‐electron transfer‐induced oxidation process is responsible for the tunable selectivity control. [ABSTRACT FROM AUTHOR]

Chemoselective hydrogenation of α,β‐epoxy ketones and α‐ketoamides is achieved at room temperature (25 °C) using 2.0 bar H2 and a pincer‐ligated Mn(I) catalyst that provides synthetically valuable α‐hydroxy epoxides and α‐hydroxy amides. This protocol applies to a wide range of alkyl‐ and aryl‐substituted α,β‐epoxy ketones, including terpenes (α‐ionone, nootkatone, and R‐carvone)‐ and steroids (testosterone and progesterone)‐derived epoxy ketones, and tolerates H2 sensitive functionalities, such as halides, acetyl, nitrile, nitro, epoxide, alkenyl and alkynyl groups. Additionally, α‐ketoamides bearing reducible functional groups, including acetyl and diazo benzene, were untouched under this protocol and selectively converted to α‐hydroxy amides. A preliminary mechanistic study highlighted the metal‐ligand cooperative H2 activation process. [ABSTRACT FROM AUTHOR]

A simple and efficient approach for the S‐arylation of tetrazole‐5‐thiol using copper oxide nanoparticles has been developed. Recently, heterocyclic thiols have attracted a great deal of interest due to their diverse biological and pharmacological properties. Thus, great efforts have been devoted in introducing efficient protocols for the synthesis of such compounds. The utilization of copper oxide nanoparticles has been substantially chosen for catalysis due to their low cost, high surface area, sustainability, and reusability. The distinctive features of this methodology involve a ligand‐free catalytic system, simple reaction procedure, shorter reaction time, wide substrate scope compatibility, and high yield of the products. [ABSTRACT FROM AUTHOR]

The direct electrochemical reduction of nicotinamide adenine dinucleotide (NAD+) results in various products, complicating the regeneration of the crucial 1,4‐NADH cofactor for enzymatic reactions. Previous research primarily focused on steady–state polarization to examine potential impacts on product selectivity. However, this study explores the influence of dynamic conditions on the selectivity of NAD+ reduction products by comparing two dynamic profiles with steady‐state conditions. Our findings reveal that the main products, including 1,4‐NADH, several dimers, and ADP‐ribose, remained consistent across all conditions. A minor by–product, 1,6‐NADH, was also identified. The product distribution varied depending on the experimental conditions (steady state vs. dynamic) and the concentration of NAD+, with higher concentrations and overpotentials promoting dimerization. The optimal yield of 1,4‐NADH was achieved under steady–state conditions with low overpotential and NAD+ concentrations. While dynamic conditions enhanced the 1,4‐NADH yield at shorter reaction times, they also resulted in a significant amount of unidentified products. Furthermore, this study assessed the potential of using pulsed electrochemical regeneration of 1,4‐NADH with enoate reductase (XenB) for cyclohexenone reduction. [ABSTRACT FROM AUTHOR]

The objective of this study is to investigate a new procedure for specifically reducing the NO2 group present on the aromatic ring along with ester group. We revealed that NaBH4-FeCl2 serves as a crucial reagent in this process. The reduction mediated by NaBH4-FeCl2 exhibited remarkable chemoselectivity, yielding the wanted products in outstanding yields of up to 90-95%. Furthermore, this process was successfully utilized in the synthesis of diamino compound, and in the synthesis of 2-substituted benzimidazole derivatives The diamine compounds was condensed with various aromatic or heterocyclic carboxylic acids in the existence of EDC.HCl and catalyst DMAP. The resulting moiety or product underwent cyclization by using CH3COOH at 100-110°C. Both the reactions (coupling & cyclization) reaction completed effectively, within the minimal reaction times. The structure of created compounds was confirmed using modern spectral techniques like FT-IR, mass spectrometry, NMR. [ABSTRACT FROM AUTHOR]

Peptide cyclization has dramatic effects on a variety of important properties, enhancing metabolic stability, limiting conformational flexibility, and altering cellular entry and intracellular localization. The hydrophilic, polyfunctional nature of peptides creates chemoselectivity challenges in macrocyclization, especially for natural sequences without biorthogonal handles. Herein, we describe a gaseous sulfonyl chloride derived reagent that achieves amine–amine, amine–phenol, and amine–aniline crosslinking through a minimalist linchpin strategy that affords macrocyclic urea or carbamate products. The cyclization reaction is metal‐mediated and involves a novel application of sulfine species that remains unexplored in aqueous or biological contexts. The aqueous method delivers unique cyclic or bicyclic topologies directly from a variety of natural bioactive peptides without the need for protecting‐group strategies. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Lewis base catalyzed and Brønsted acid controlled chemodivergent electrophilic selenofunctionalizations of alkynes were developed for the first time. Various selenium‐containing tetrasubstituted alkenes were readily obtained in moderate to excellent yields with complete E/Z selectivities. As the substrates were 1‐ethynyl naphthol derivatives, linear selenium‐containing tetrasubstituted alkenes were produced via intermolecular oxygen nucleophilic attack in the absence of acid additive; in contrast, cyclic selenium‐containing tetrasubstituted alkenes were generated through intramolecular carbon nucleophilic capture with the addition of Brønsted acid. [ABSTRACT FROM AUTHOR]

Optimizing lanthanide catalyst performance with organic ligands often encounters significant challenges, including susceptibility to water or oxygen and complex synthesis pathways. To address these issues, our research focuses on developing inorganic lanthanide clusters with enhanced stability and functionality. In this study, we introduce the [Sm6O(OH)8(H2O)24]I8(H2O)8 cluster (Sm-OC) as a sustainable and efficient catalyst for the aerobic oxidation of thiols under heating conditions. The Sm-OC catalyst demonstrated remarkable stability, outstanding recyclability, and excellent chemoselectivity across a diverse range of functional groups in 38 different tests. Notably, it enables efficient unsymmetrical disulfide synthesis and prevents the formation of over-oxidized by-products, highlighting its superior performance. This Sm-OC catalyst provides a practical and robust tool for the precise construction of versatile disulfides, thus establishing a template for the broader use of lanthanide clusters in organic synthesis. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Lewis base catalyzed and Brønsted acid controlled chemodivergent electrophilic selenofunctionalizations of alkynes were developed for the first time. Various selenium‐containing tetrasubstituted alkenes were readily obtained in moderate to excellent yields with complete E/Z selectivities. As the substrates were 1‐ethynyl naphthol derivatives, linear selenium‐containing tetrasubstituted alkenes were produced via intermolecular oxygen nucleophilic attack in the absence of acid additive; in contrast, cyclic selenium‐containing tetrasubstituted alkenes were generated through intramolecular carbon nucleophilic capture with the addition of Brønsted acid. [ABSTRACT FROM AUTHOR]

We describe herein the additive‐controlled divergent [4+2] cycloaddition and 1,4‐Michael addition reaction of benzofuran‐derived azadienes (BDAs) with enamides. An unprecedented [4+2] cycloaddition reaction of BDAs and enamide compounds was developed in the presence of 4 Å MS, providing a variety of structurally complex decahydrobenzofuro[3,2‐b]quinolines (13 examples) in moderate to excellent yields (59–98 % yields) with single diastereoisomer obtained. While employing MgSO4 as desiccant, the chemoselectivity was switched to the 1,4‐addition reactions, leading to a wide range of highly functionalized hybrids of benzofurans and enamide compounds (25 examples) in 25–94 % yields under mild conditions. [ABSTRACT FROM AUTHOR]

Research on the chemoselective metal‐catalyzed hydrogenation of conjugated π‐systems has mostly been focussed on enones. Herein, we communicate the understudied asymmetric hydrogenation of enimines catalyzed by N,P‐iridium complexes and chemoselective toward the alkene. A number of enoxime ethers underwent hydrogenation smoothly to yield the desired products in high yield and stereopurity (up to 99 % yield, up to 99 % ee). No hydrogenation of the C=N π‐bond was observed under the applied reaction conditions (20 bar H2, rt, DCM). It was demonstrated that the chiral oxime ether could be hydrolyzed into the ketone with complete preservation of the installed stereogenity at the α‐carbon. At last, a binding mode of the substrate to the active iridium catalyst and the consequence for the stereoselective outcome was proposed. [ABSTRACT FROM AUTHOR]

The tert‐butyl group is a common aliphatic motif extensively employed to implement steric congestion and conformational rigidity in organic and organometallic molecules. Because of the combination of a high bond dissociation energy (~100 kcal mol−1) and limited accessibility, in the absence of directing groups, neither radical nor organometallic approaches are effective for the chemical modification of tert‐butyl C−H bonds. Herein we overcome these limits by employing a highly electrophilic manganese catalyst, [Mn(CF3bpeb)(OTf)2], that operates in the strong hydrogen bond donor solvent nonafluoro‐tert‐butyl alcohol (NFTBA) and catalytically activates hydrogen peroxide to generate a powerful manganese‐oxo species that effectively oxidizes tert‐butyl C−H bonds. Leveraging on the interplay of steric, electronic, medium and torsional effects, site‐selective and product chemoselective hydroxylation of the tert‐butyl group is accomplished with broad reaction scope, delivering primary alcohols as largely dominant products in preparative yields. Late‐stage hydroxylation at tert‐butyl sites is demonstrated on 6 densely functionalized molecules of pharmaceutical interest. This work uncovers a novel disconnection approach, harnessing tert‐butyl as a potential functional group in strategic synthetic planning for complex molecular architectures. [ABSTRACT FROM AUTHOR]

The efficient and promising solvent-free method, catalyzed by Sulphated Tin oxide (SO42-/SnO2), has been developed for the synthesis of 1,3,5-triarylbenzene and its derivatives. The Bronsted acidic surfactant catalyst facilitates quick results and high yields, offering additional advantages such as easy separation and reusability with almost the same efficiency for subsequent cycles. This protocol involves the self-condensation of three molecules through cyclotrimerization with high chemo-selectivity. The substrate methyl phenyl ketone contains both electronwithdrawing and electron-donating groups, which assemble the target moiety with high and low yields, respectively. The synthesized compounds are evaluated through in silico studies to assess their drug-likeness properties. [ABSTRACT FROM AUTHOR]

The irradiation of β‐enaminones, generated in situ from cyclic 1,3‐diketones and activated alkenes leads to polyheterocyclic skeletons. The photoproduct chemoselectivity depends on the type of cyclic 1,3‐diketones employed viz., 2‐acetylcyclopentanone and 2‐acetylcyclohexanone. The observed chemoselectivity was rationalized based on the Dieckmann‐Kon rule. [ABSTRACT FROM AUTHOR]

1,2-Difunctionalization of alkynes offers a straightforward approach to access polysubstituted alkenes. However, simultaneous multi-component cascade transformations including difunctionalization of two alkynes with both syn- and anti-selectivity in one catalyst system is undeveloped and proves to be a significant challenge. Herein, we report a Nickel-catalyzed four-component reaction to access polysubstituted 1,3-dienes using two terminal alkynes, aryl boroxines, and perfluoroalkyl iodides, wherein the reaction forms three new C-C bonds in a single vessel and serve as a modular strategy to access polysubstituted 1,3-dienes with excellent chemoselectivity, good regioselectivity and exclusive stereoselectivity. Control experiments reveal the plausible reaction mechanism and DFT calculations explain the cause for the formation of this unusual four-component reaction. Furthermore, we successfully incorporate two biologically active units into 1,2,3,4-tetrasubstituted 1,3-dienes, which greatly increases the diversity of molecular scaffolds and brings more potential values to medicinal chemistry, the synthetic utility of our protocol is further demonstrated by the late-stage transformations. Multi-component cascade transformations including difunctionalization of two alkynes with both syn- and anti-selectivity in one catalyst system is challenging. Herein, the authors report a Nickel-catalyzed four-component reaction to access densely substituted 1,3-dienes using two terminal alkynes, aryl boroxines, and perfluoroalkyl iodides. [ABSTRACT FROM AUTHOR]

A novel catalytic system for radical cross‐coupling reactions based on copper and chiral Pyridyl‐bis(imidazole) (PyBim) ligands is described. It overcomes the challenges of chemoselectivity and enantioselectivity, achieving a highly enantioselective vicinal sulfonyl‐esterification reaction of alkenes involving sulfur dioxide. This strategy involves the use of earth‐abundant metal catalyst, mild reaction conditions, a broad range of substrates (84 examples), high yields (up to 97% yield), and exceptional control over enantioselectivity. The reaction system is compatible with different types of radical precursors, including O‐acylhydroxylamines, cycloketone oxime esters, aryldiazonium salts, and drug molecules. Chiral ligand PyBim is identified as particularly effective in achieving the desired high enantioselectivity. Mechanistic studies reveal that copper/PyBim system plays a vital role in C─O coupling, employing an outer‐sphere model. In addition, the side arm effect of ligand is observed. [ABSTRACT FROM AUTHOR]

Tempted by the unique medicinal and biological potential of indole‐containing heterocycles, chemists, especially those specializing in heterocycle synthesis and drug discovery, are actively pursuing their efficient construction. This review spotlights the latest advancements in microwave‐assisted (M. W.) synthesis of diverse indole‐based heterocyclic compounds. We systematically categorize the reported methods based on the specific indole substitution patterns. This review concise the microwave assisted synthesis of indole based‐pyridine derivatives, indole based‐pyrimidine, indole based‐oxindole, spiro‐oxindole, Fischer indole Heck‐isomerization derivatives, functionalized indole, substituted indoles, indolyl quinoline, indole triazole and indolylnicotinonitriles derivatives. Ultimately, this review aims to provide organic and medicinal chemists with a concise yet informative guide to recent methodologies employing indole derivatives in the microwave‐powered synthesis of heterocycles. [ABSTRACT FROM AUTHOR]

Transition metal‐catalyzed C−H arylation polymerization (CHAP) is an attractive tool for constructing π‐conjugated polymers in a sustainable manner. However, the existing methods primarily rely on palladium catalysis, which usually entails harsh reaction conditions and branching/cross‐linking. Here we report the first example of an ambient‐temperature ruthenium‐catalyzed C−H arylation polymerization induced by visible light irradiation. The present polymerization can produce various meta‐ and para‐linked polymers in excellent yields with high molecular weights. The remarkable feature of our mild reaction platform is represented by high chemoselectivity, leading to polymers that are otherwise inaccessible under conventional reaction conditions at high temperatures. [ABSTRACT FROM AUTHOR]