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An oxidative strategy is reported to access α-oxo BMIDA gold carbenes directly from BMIDA-terminated alkynes. Besides offering expedient access to seldom studied boryl metal carbenes, these BMIDA gold carbene species undergo facile insertions into methyl, methylene, methine, and benzylic C-H bonds in the absence of the Thorpe-Ingold effect. They also undergo efficient OH insertion, cyclopropanation, and F-C alkylations. This chemistry provides rapid access to structurally diverse α-BMIDA ketones, which are scarcely documented. In combination with DFT studies, the role of BMIDA is established to be an electron-donating group that attenuates the high electrophilicity of the gold carbene center.

Panowamycins are a group of isochroman-based natural products first isolated from Streptomyces sp. K07-0010 in 2012 by Satoshi Ōmura and co-workers that exhibit modest anti-trypanosomal activity. Herein we demonstrate the first syntheses of these natural products and their epimers. Stereoselective dirhodium-catalyzed C-H insertion reactions with a donor/donor carbene construct the substituted isochroman core in the key bond-forming step. The syntheses are completed without the use of protecting groups and feature a late-stage Wacker oxidation. Incongruent NMR spectra between natural and synthetic samples revealed the structural misassignment of panowamycin A and veramycin F. Computational NMR studies suggested panowamycin A to be an alternate diastereomer, which was confirmed by synthesizing this isomer. Concurrent with this work, in 2021 Mahmud and co-workers came to the same conclusion with an updated NMR analysis of panowamycin A. In a divergent, asymmetric sequence, we report the synthesis of panowamycin A, panowamycin B, TM-135, and veramycin F.

In this study, the reactivity of the alkyl nitrenes, generated from the substituted hydroxylamine precursors, was determined using the same rhodium catalyst. The results revealed that in competitive C–H insertion experiments, the regioselectivity between benzylic and tertiary C–H bonds could be modulated by adding Brønsted acids or changing the substituents on oxygen. This study enhances our understanding of the metallonitrene structures and provides valuable insights for further development of selective N-heterocycle syntheses.

Donor/donor carbenes are relatively new in the field of carbene chemistry; although applications in C-H and X-H insertion reactions are few in number, they demonstrate exquisite chemo- and stereo-selectivity. Recent reports have shown that C-H, N-H, B-H, O-H, S-H, Si-H, Ge-H, Sn-H and P-H insertion reactions are feasible with a variety of transition metal catalysts, both inter- and intramolecularly. Furthermore, high degrees of diastereo- and enantioselectivity have been observed in several cases. Methods typically involve the formation of a diazo-based carbene precursor, but procedures using diazo-free metal carbenes have been developed with significant success. This Minireview covers transition-metal catalyzed insertion reactions with donor/donor and donor carbenes, providing context for future developments in this emerging field.

Cyclobutanones are synthetically versatile compounds that often require extensive effort to access. Herein, we report a facile synthesis of cyclobutanones based on the C(sp3 )-H insertion chemistry of oxidatively generated gold carbenes. Various cyclobutanones were obtained in synthetically useful yields from substrates with minimal structural prefunctionalization. This discovery reveals new synthetic utilities of gold-catalyzed oxidative transformations of alkynones.

Insertion reactions of donor/donor carbenes have emerged from obscurity to become a versatile method for the synthesis of a variety of cyclic structures with excellent control of diastereo- and enantioselectivity. This Account describes the origin of this project as part of a natural product synthesis and the ensuing decade of reaction development that has resulted in new asymmetric methods as well as intriguing tangential observations.

(E)-3-Arylidene-4-diazopyrrolidine-2,5-diones previously shown to yield two products in reactions with tetrahydrofuran mediated by rhodium carbenes—tetrahydrofur-2-yl-substituted product of C-H insertion and spirocyclic product of formal C-O insertion. Accidentally, it was noted that the ratio of the two products depends on the catalyst loading, and the phenomenon was investigated in detail. It was found to be of preparative significance: by solely changing the catalyst loading from 0.01 mol% to 10 mol%, one can obtain sound yields of either of the two products. Mechanistic and kinetic interpretation of this new phenomenon has been proposed. [ABSTRACT FROM AUTHOR]

We employ a single catalyst/oxidant system to enable the asymmetric syntheses of indolines, benzodihydrothiophenes, and indanes by C-H insertion of donor/donor carbenes. This methodology enables the rapid construction of densely substituted five-membered rings that form the core of many drug targets and natural products. Furthermore, oxidation of hydrazones to the corresponding diazo compounds proceeds in situ, enabling a relatively facile one- or two-pot protocol in which isolation of potentially explosive diazo alkanes is avoided. Regioselectivity studies were performed to determine the impact of sterics and electronics in donor/donor metal carbene C-H insertions to form indolines. This methodology was applied to a variety of substrates in high yield, diastereomeric, and enantiomeric ratios and to the synthesis of a patented indane estrogen receptor agonist with anti-cancer activity.

Photolithography is an important process in semiconductor technology with the aim to create structured surfaces, but often requires specific substrate materials that have to be pretreated. Using a novel, fast, and simple process based on thermal activation, the authors are able to produce spatially controlled surface‐bound polymer networks on a variety of different common materials. In this process, which is similar to branding livestock or wood with a hot branding iron, a hot stamp is brought into direct contact with a diazo group‐containing copolymer applied to a substrate to map the profile of the stamp into the polymer film. Crosslinking and covalent surface attachment to the substrate are achieved as a result of thermal activation of the diazo groups, leading to carbene formation, which induces C,H‐insertion crosslinking (CHic). After dissolving the uncrosslinked material, the shape of the stamp is transferred into the polymer film. The polymer systems used here allow activation of the diazo function at mild temperatures, so that relatively fast processing allows the performance of step‐and‐repeat processes. By recoating and then repeating the process on already structured surfaces, the physical and chemical material properties of structures can be tailored, and structure‐on‐structure features become easily possible. [ABSTRACT FROM AUTHOR]

In this study, azidoformate (AF) is investigated as a reactive functional group to mediate noncatalytic C–H insertion reactions to interconnect polypropylene (PP) chains to generate long-chain branches (LCBs). 4,4′-Isopropylidenediphenyl azidoformate (DAF) with two terminal AF groups is synthesized, which is first mixed with propylene/α-olefin copolymer at 100 °C. Then, the prepared mixture with a predetermined amount of DAF is reactively melt mixed with PP at 165 °C. This unique two-step preparation strategy affords PP with prominent rheological properties of LCBs, e.g., shear thinning and strain hardening. The rheological characteristics are easily controlled by adjusting the amount of DAF to afford an effective tool to prepare high-melt-strength PPs. The strength of this strategy is distinct, including a simple/typical melt processing procedure, no degradation of PP chains, and no purification/solvent recycling steps. The C–H insertion capability of azidoformate groups suggests an expandability of this methodology as a platform technology to prepare modified polymers.

Herein we have discussed projects related to blue LED mediated C-H and N-H insertion reaction in indoles and related heterocycles with aryl diazoesters and iodonium ylides as sources of carbenes. Blue LED effectively facilitates these conversions and was optimized from the option of numerous other LED lights. No metal catalysts were required. The reactions provide formation of differently alkylated indoles, pyrroles and furans. Control experiments and DFT calculation were used to understand the mechanism of reactions. As an application compounds bearing azepino[4, 5-b]indole and spiropiperidino indole building blocks were synthesized from the alkylated products.

This study presents a comprehensive investigation into the preparation of functionalized polypropylene (PP) with different functional groups, such as amino-, hydroxyl-, acetamido-, and carboxyl-groups, utilizing efficient C –H insertion capability of sulfonyl azide (SA) compounds with the functional groups. The reactive melt mixing of PP and the SA compounds was performed at temperatures determined by the decomposition temperatures of the SA groups, followed by purification processes to remove unreacted SA compounds, confirming the establishment of stable covalent linkages between the SA compounds and PP chains. Grafting efficiency (GE) values were determined using FT-IR spectroscopy, showcasing efficient grafting of the SA compounds onto PP chains with GE values ranging from 60 % to 70 %. Remarkably, SA compound with carboxyl functional group exhibited an exceptionally high GE value of ∼90 %, likely attributed to its electron-withdrawing carbonyl group. XRD analyses, thermal analyses, morphological analyses of cryogenically fractured modified PPs and mechanical property analyses revealed successful incorporation of SA compounds into PP chains with relatively low sensitivity of the crystal structure of the modified PPs to the incorporated SA compounds. Hydrophilicity assessments revealed improved paint adhesion capabilities of the modified PP surfaces, highlighting the potential for the tailored surface modification strategies to enhance material characteristics. [Display omitted] • A method for introducing functional groups onto PP is demonstrated. • Sulfonyl azide compounds with various functional groups are used. • The method achieves high grafting efficiency values ranging from 60 % to 90 %. • The PPs exhibit enhanced hydrophilicity and improved paint adhesion capabilities. • The potential of this method for tailoring surface properties of PP is highlighted. [ABSTRACT FROM AUTHOR]

(E)-3-Arylidene-4-diazopyrrolidine-2,5-diones previously shown to yield two products in reactions with tetrahydrofuran mediated by rhodium carbenes—tetrahydrofur-2-yl-substituted product of C-H insertion and spirocyclic product of formal C-O insertion. Accidentally, it was noted that the ratio of the two products depends on the catalyst loading, and the phenomenon was investigated in detail. It was found to be of preparative significance: by solely changing the catalyst loading from 0.01 mol% to 10 mol%, one can obtain sound yields of either of the two products. Mechanistic and kinetic interpretation of this new phenomenon has been proposed.

By using diazonaphthoquinones and anilines as key reagents and through a point‐to‐axis chiral transfer strategy, the atroposelective synthesis via asymmetric C(sp2)−H bond insertion reaction of arenes has been realized under rhodium catalysis, providing the resulting biaryl atropisomers in moderate to excellent yields with good enantiomeric ratios (up to 99:1). Further elaboration indicates this type of axially biaryl scaffold may have promising potentials in developing novel chiral ligands. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: Transition‐metal‐catalyzed C—H insertion of metal‐carbene represents an excellent and powerful approach for C—H functionalization. However, despite remarkable advances in metal‐carbene chemistry, transition metal catalysts that are capable of enantioselective intermolecular carbene C—H insertion are mainly constrained to dirhodium(II) and iridium(III)‐based complexes. Herein, we disclose a new version of asymmetric carbene C—H insertion reaction with rhodium(I) catalyst. A highly enantioselective rhodium(I) complex‐catalyzed C(sp3)—H functionalization of 1,4‐cyclohexadienes with α‐aryl‐α‐diazoacetates was successfully developed. By using chiral bicyclo[2.2.2]‐octadiene as ligand, rhodium(I)‐carbene‐induced asymmetric intermolecular C—H insertion proceeds smoothly at room temperature, allowing access to a diverse variety of α‐aryl‐α‐cyclohexadienyl acetates and gem‐diaryl‐containing acetates in good yields with good to excellent enantioselectivities (up to 99% ee). Furthermore, the synthetic utility of the reaction was highlighted by facile synthesis of a novel cannabinoid CB1 receptor ligand. This method may offer a new opportunity for the development of therapeutically exploitable cannabinoid receptor type ligands in medicinal chemistry. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: Transition‐metal‐catalyzed C—H insertion of metal‐carbene represents an excellent and powerful approach for C—H functionalization. However, despite remarkable advances in metal‐carbene chemistry, transition metal catalysts that are capable of enantioselective intermolecular carbene C—H insertion are mainly constrained to dirhodium(II) and iridium(III)‐based complexes. Herein, we disclose a new version of asymmetric carbene C—H insertion reaction with rhodium(I) catalyst. A highly enantioselective rhodium(I) complex‐catalyzed C(sp3)—H functionalization of 1,4‐cyclohexadienes with α‐aryl‐α‐diazoacetates was successfully developed. By using chiral bicyclo[2.2.2]‐octadiene as ligand, rhodium(I)‐carbene‐induced asymmetric intermolecular C—H insertion proceeds smoothly at room temperature, allowing access to a diverse variety of α‐aryl‐α‐cyclohexadienyl acetates and gem‐diaryl‐containing acetates in good yields with good to excellent enantioselectivities (up to 99% ee). Furthermore, the synthetic utility of the reaction was highlighted by facile synthesis of a novel cannabinoid CB1 receptor ligand. This method may offer a new opportunity for the development of therapeutically exploitable cannabinoid receptor type ligands in medicinal chemistry. [ABSTRACT FROM AUTHOR]

[Display omitted] • Methods of functionalization of unactivated positions on steroids are reported. • Development of reagents for remote functionalization is mentioned. • Syntheses of biologically active steroids from commercially available analogs using remote functionalization are discussed. Research published between 2001 and 2022 on the functionalization of remote positions of steroids, as well as the use of this technique in the generation of biologically active compounds has been reviewed. In the first section of the analysis established and novel methods for activation of sites deemed to be remote were reported. A series of manganese- (mainly), rhodium-, ruthenium- and osmium-centered porphyrins as catalysts in the presence of PIDA as oxidant have effected hydroxylation at C-1, -5, -6, -7, -11, -14, -15, -16, -17, -20, -24 and -25. Dioxiranes have been utilized in inserting hydroxyl groups at the 5, 12, 14, 15, 16, 17, 20, 24 and 25 positions (tertiary centers for the most part). Alcohols at C-12 and -16 were oxidized further to ketones. The Schönecker oxidation, discovered and developed during the period, has revolutionized the selective functionalization at C-12 of steroids possessing a 17-keto group. In the presence of iron-centered PDP- and MCP-based catalysts, hydrogen peroxide and acetic acid, substrates tended to be hydroxylated at C-6 and -12, with further oxidation to ketones often accompanying this reaction. The hypohalite reaction, utilizing the more modern Suarez conditions (irradiation in the presence of iodine and PIDA), was reported to facilitate the insertion of a hydroxyl moiety five atoms away from an existing alcohol oxygen. Steroidal-3β-diazoacetates tend to decompose on heating with di-rhodium-centered catalysts while activating carbons four or five atoms away. Chromium- and iron-based acetates were observed to functionalize C-5 and -25. Other reactions involving ring cleavage and halogenation, ketone irradiation and α-hydroxylation of ethers were also covered. The syntheses of compounds with marked biological activity from readily available steroids is described in the second section of the study. Cyclopamine, cephalostatin-1, ritterazine B and three polyhydroxypregnanaes (pergularin, utendin and tomentogenin) were generated in sequences in which a key step required hydroxylation at C-12 using the Schönecker reaction. A crucial stage in the preparation of cortistatin A, the saundersioside core, eurysterol A, 5,6-dihydroglaucogenin C, as well as clinostatins A and B involved the functionalization of C-18 or -19 utilizing hypohalite chemistry. The synthetic route to xestobergsterol A, pavonin-4-aglycone and ouagabagenin included a transformation where ketone irradiation played a part in either producing a Δ14 or a C-19 activated steroid. The radical relay reaction, where a 17α-chloro-steroid was formed, was central in the generation of pythocholic acid. The lead tetraacetate reaction was pivotal in the functionalization of C-19 during the synthesis of cyclocitrinol. [ABSTRACT FROM AUTHOR]

The sensitized photoexcitation of 2-diazocyclopentane-1,3-diones in the presence of THF leads to the insertion of the terminal N-atom of the diazo group into the α-С–Н bond of THF, producing the associated N-alkylhydrazones in yields of up to 63–71%. Further irradiation of hydrazones derived from furan-fused tricyclic diazocyclopentanediones culminates in the cycloelimination of furans to yield 2-N-(alkyl)hydrazone of cyclopentene-1,2,3-trione. By contrast, the direct photolysis of carbocyclic diazodiketones gives only Wolff rearrangement products with up to 90–97% yield.

In this study, the reactivity of the alkyl nitrenes, generated from the substituted hydroxylamine precursors, was determined using the same rhodium catalyst. The results revealed that in competitive C-H insertion experiments, the regioselectivity between benzylic and tertiary C-H bonds could be modulated by adding Brønsted acids or changing the substituents on oxygen. This study enhances our understanding of the metallonitrene structures and provides valuable insights for further development of selective N-heterocycle syntheses., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Noda, Asada and Shibasaki.)

Gold vinylidenes have recently emerged as useful intermediates in synthetic organic chemistry. These species, which can principally be accessed by a 1,2-migration process from a gold-activated alkyne or by dual gold catalysis on a diyne substrate, can react with nucleophilic partners or by C–H insertion to produce a variety of functionalized (poly)cyclic compounds. This short review covers the synthetic approaches developed so far to access gold vinylidenes and the different reactivities these species can exhibit. 1 Introduction 2 1,2-Migration Processes 3 Dual Gold Catalysis 4 Other Processes 5 Conclusion [ABSTRACT FROM AUTHOR]

Excellent enantioselectivities of up to 98 % ee are achieved by employing the copper‐bis(oxazoline)‐NaBARF catalyst system in the C–H insertion reactions of α‐diazo‐β‐oxo sulfones. The influence of variation of the bis(oxazoline) ligand, copper salt, additive and substrate on both the efficiency and the enantioselectivities of these intramolecular C–H insertion reactions has been explored. Optimum enantioselectivities are achieved with phenyl and diphenyl ligands across the substrate series. [ABSTRACT FROM AUTHOR]

The stereoselective synthesis of 5,5-spiroacetals by Rh(II)-catalysed double C–H insertion of methylene acetals bearing two diazo ester substituents is described. The diastereoselectivity of this bidirectional approach can be tuned through appropriate choice of catalyst, and chiral catalysts lead to products with up to 89% ee . The diastereoselectivity of the first cyclisation suggests that the second cyclisation proceeds via a non-concerted pathway. [ABSTRACT FROM AUTHOR]

The intramolecular C-H insertions of carbenes derived from 2-diazo-2-sulfamoylacetamides were studied. 2-Diazo-2-sulfamoylacetamides were first prepared from chloroacetyl chloride and secondary amines through acylation followed by sequential treatments with sodium sulfite, phosphorus oxychloride, secondary amines, and 4-nitrobenzenesulfonyl azide. The results indicate that: (1) 2-diazo-N,N-dimethyl-2-(N,N-diphenylsulfamoyl)acetamide can take the formal aromatic 1,5-C-H insertion in its N-phenylsulfonamide moiety to afford the corresponding 1,3-dihydrobenzo[c]isothiazole-3-carboxamide 2,2-dioxide derivative; (2) no aliphatic C-H insertions occur for 2-diazo-2-(N,N-dialkylsulfamoyl)acetamides; and (3) for 2-diazo-N-phenyl-2-(N-phenylsulfamoyl)acetamides, the formal aromatic 1,5-C-H insertion in the N-phenylacetamide moiety is favorable to afford the corresponding 3-sulfamoylindolin-2-one derivatives as sole or major products. The intramolecular competitive aromatic 1,5-C-H insertion reactions of 2-diazo-2-sulfamoylacetamides with aryl groups on both amide and sulfonamide groups reveal that the N-aryl substituents on acetamide are more active than those on sulfonamide. The chemoselectivity is controlled by electronic effect of the aryl group.

The advent of C(sp³)-H functionalization has heralded a paradigm shift in natural product synthesis. Indeed, several reports in which C-H functionalization serves as the key step in the synthesis have appeared over the years. The purpose of this Microreview is briefly to summarize total syntheses reported during 2014-2016 with emphasis on the most innovative results relating to C-H functionalization. In addition, new advances in the field of Rh- and Pd-catalyzed C(sp³)-H functionalization are discussed with the aim of providing readers with new disconnection ideas for their total synthesis endeavors. [ABSTRACT FROM AUTHOR]

Copper triflate mediated α-monohalogenation of α-diazo β-ketosulfones with ammonium halides provides the corresponding α-halo β-ketosulfones. Different metal triflates are investigated for this facile and efficient transformation. A plausible mechanism is proposed. [ABSTRACT FROM AUTHOR]

A stereoselective synthesis of 2,3-dihydro-1H-indoles with a RhII-catalyzed C–H insertion is reported. The α-diazo carbonyl intermediates can be obtained by a diazo-transfer reaction of 2-aminophenylacetic acids. Optimization and kinetic studies were performed, which resulted to increased yields of the diazo transfer after mechanistic evaluation of the side-product formation. trans-2,3-Dihydro-1H-indoles were obtained in high diasteromeric excesses (up to 94 % de) and enantiomeric excesses (up to 94 % ee). [ABSTRACT FROM AUTHOR]

A dirhodium(II) carboxylate catalyst bearing axially chiral amino acid derivatives is prepared. X-ray crystal structure analysis reveals that four of the bridging ligands are aligned in a C2-symmetry-like conformation. This catalyst is effective in the asymmetric intramolecular C-H insertion of α-aryl-α-diazoacetates to α-aryl-β-substituted γ-lactones with a reasonable level of diastereo- and enantioselectivity, especially in the reaction of phenyl- and β-naphthyl-substituted substrates. [ABSTRACT FROM AUTHOR]

Intramolecular C–H insertion reactions of α-diazocarbonyl compounds typically proceed with preferential five-membered ring formation. However, the presence of a heteroatom such as nitrogen can activate an adjacent C–H site towards insertion resulting in regiocontrol issues. In the case of α-diazoacetamide derivatives, both β- and γ-lactam products are possible owing to this activating effect. Both β- and γ-lactam products are powerful synthetic building blocks in the area of organic synthesis, as well as a common scaffold in a range of natural and pharmaceutical products and therefore C–H insertion reactions to form such compounds are attractive processes. [ABSTRACT FROM AUTHOR]

In this study, azidoformate (AF) is investigated as a reactive functional group to mediate noncatalytic C–H insertion reactions to interconnect polypropylene (PP) chains to generate long-chain branches (LCBs). 4,4′-Isopropylidenediphenyl azidoformate (DAF) with two terminal AF groups is synthesized, which is first mixed with propylene/α-olefin copolymer at 100 °C. Then, the prepared mixture with a predetermined amount of DAF is reactively melt mixed with PP at 165 °C. This unique two-step preparation strategy affords PP with prominent rheological properties of LCBs, e.g., shear thinning and strain hardening. The rheological characteristics are easily controlled by adjusting the amount of DAF to afford an effective tool to prepare high-melt-strength PPs. The strength of this strategy is distinct, including a simple/typical melt processing procedure, no degradation of PP chains, and no purification/solvent recycling steps. The C–H insertion capability of azidoformate groups suggests an expandability of this methodology as a platform technology to prepare modified polymers. • Long-chain branched polypropylene is prepared via reactive melt mixing procedures. • Noncatalytic C–H insertion capability of azidoformate is utilized. • Propylene/α-olefin copolymer is employed as a dispersant of di (azidoformate). • The amount of branches is controlled by adjusting the amount of di (azidoformate). • Elastic and strain hardening melt behaviors of the resulting polymer are observed. [ABSTRACT FROM AUTHOR]

The effect of Rh- and Ir-centers on the optical properties of the BODIPY core has been studied. To this end, novel metal complexes tethered to BODIPY have been prepared through an easy and versatile procedure using N-directed C-H activation reactions. The organometallic moiety has a tremendous influence on the emissive properties of the BODIPY fragment. A photoinduced electron transfer (PET) mechanism is suggested to be the main mechanism responsible for the suppression of the BODIPY fluorescence emission in the newly formed dyads. The efficiency of the PET depends on both the distance between the chromophores in the dyad and the nature of the transition metal (Rh vs. Ir). [ABSTRACT FROM AUTHOR]

C-H insertion and amide insertion reactions using metal-carbene species provide a powerful synthetic method for direct functionalization of kinetically inert or thermodynamically stable chemical bonds. Our group previously developed an amide insertion reaction using a rhodium-dimer complex, constructing an array of nitrogen-bridged heterocycles. Another research group reported C-H insertion reactions using structurally related substrates and rhodium catalysts. Detailed mechanistic studies were not provided, however, and therefore, the origin of the chemoselectivity was ambiguous. Here we describe our theoretical investigation of the chemoselectivity between the amide insertion reaction and C-H functionalization. An energy gap of the identified transition states in the reaction coordinates could support the reported experimental results and the observed chemoselectivity. Moreover, frontier molecular orbital analysis revealed that functionalities adjacent to the metal-carbene species could affect orbital populations and their energy levels, resulting in the construction of a completely distinctive ring system.

A system for the synthesis of α-alkylidene-γ-butyrolactones via a one-pot C–H insertion/olefination sequence is described. The process is based on the rhodium catalysed C–H insertion reaction of α-diazo-α-(diethoxyphosphoryl)acetates. The mild reaction conditions, operational simplicity and ready availability of starting materials are all key features. A wide range of successful reaction systems are reported (41 examples) highlighting the generality of the method. The application of this method in the total synthesis of the natural products (±)-cedarmycins A and B is also described. [ABSTRACT FROM AUTHOR]

An asymmetric synthesis of (−)- E -δ-viniferin, a trans -resveratrol dimer natural product containing a dihydrobenzofuran ring, has been achieved by exploiting a Rh(II)-catalyzed intramolecular C–H insertion reaction of a diaryldiazomethane derivative as a key step. The C–H insertion under catalysis by dirhodium(II) tetrakis[ N -tetrafluorophthaloyl-( S )- tert -leucinate], Rh 2 ( S -TFPTTL) 4 , provided the 2,3-diaryl-2,3-dihydrobenzofuran core structure with perfect cis diastereoselectivity and 96% ee. [ABSTRACT FROM AUTHOR]

The intramolecular C–H insertion of the Mes*-substituted phosphanylidenecarbene [Mes*P=C:] (Mes* = 2,4,6-t-Bu3C6H2) and characters of the cyclization product, 6,8-di-tert-butyl-3,4-dihydro-4,4-dimethyl-1-phosphanaphthalene, were studied based on ab initio and density functional theory calculations. [ABSTRACT FROM PUBLISHER]

Intramolecular C–H insertion on diazosulfone and diazosulfonate substrates was used to prepare synthetically useful intermediates from easily available starting materials. [ABSTRACT FROM AUTHOR]

An approach to aberrarone, an antimalarial diterpenoid natural product with tetracyclic skeleton is reported. Key to the stereoselective preparation of the 6-5-5 tricyclic skeleton includes the mediation of Nagata reagent for constructing the C1 all-carbon quaternary centers and gold-catalyzed cyclopentenone synthesis through C-H insertion., (Copyright © 2022, Shi et al.)

A series of 4-fluoro-pyrazole derivatives were synthesized in moderate to good yields via a one-pot tandem procedure involving an Rh2(OAc)4-catalyzed C-H insertion and an electrophilic fluorination with N-fluorobenzenesulfonimide (NFSI). [ABSTRACT FROM AUTHOR]

Abstract: A Rh-catalyzed intramolecular aromatic C–H insertion of α-diazo β-ketoesters was developed. This protocol offers a practical strategy for the synthesis of 4-carbonyl chroman derivatives with high yield and is compatible with a wide variety of substituents. Synthetic applications of the 4-carbonyl chroman were also demonstrated. [Copyright &y& Elsevier]

Competition between C-H insertion and hydride transfer is reported for the copper-catalysed reactions of a range of phenyl-substituted α-diazo-β-keto sulfones. Control of chemoselectivity is possible by alteration of the electronic properties of the diazo substrate. The production of enantioenriched cyclopentanones (up to 89% ee), formed via C-H insertion, and alkylidene tetrahydrofurans (up to 43% ee), produced via hydride transfer, is described. The isolation of products derived from hydride transfer provides mechanistic insight into the copper-mediated C-H insertion of α-diazocarbonyl compounds. [ABSTRACT FROM AUTHOR]