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A new copper-catalyzed three-component oxidative 1,2-trifluoromethylarylation of styrenes with NaSO2CF3 and indoles involving aryl C–H bond functionalization is described. This reaction is initiated by single electron transfer upon utilizing TBPB as an oxidant, thus enabling introduction of a CF3 group and an aryl group into the C=C bond of alkenes in a single step. This method represents a highly atom and step-economical access to various CF3-substituted 1,1-diarylalkane derivatives in moderate to good yields with good functional group compatibility. [ABSTRACT FROM AUTHOR]

Functionalization of alkenes has been well investigated by chemists, thus it has been extensively applied in organic synthesis and industries. In the past few decades, transition‐metal, such as palladium, rhodium, gold, iridium, copper and iron, catalyzed functionalization reactions of alkenes have been significantly developed and played vital roles in synthesis. The difunctionalization of alkenes are appealing as an important alternative to the traditional approaches for the construction of useful carbon centers, particularly carbon quaternary centers, which commonly existed as structural motifs in numerous natural products, pharmaceuticals, and biologically active molecules. This account will summarize our recent advances in the intermolecular difunctionalization of alkenes, and also highlight the scope and limitations as well as the mechanisms of these difunctionalization reactions. In general, in this account the difunctionalization of alkenes starting from dicarbofunctionalization will be discussed. Then carboheterofunctionalization of alkenes will be intensively reviewed, and diheterofunctionalization will also be highlighted. This personal account introduces the recent advances in difunctionalization of alkenes. These reactions are classified by the chemical bond formation, including C−C, C−N, C−O and other carbon‐heteroatom bond formation. This review highlights the scope and limitations, as well as the mechanisms of these functionalization reactions. [ABSTRACT FROM AUTHOR]

Abstract: A new palladium‐catalyzed reductive [5+1] cycloaddition of 3‐acetoxy‐1,4‐enynes with CO, enabled by hydrosilanes, has been developed for delivering valuable functionalized phenols. This methodology employs hydrosilanes as the external reagent to facilitate the [5+1] carbonylative benzannulation. The reaction is a conceptually and mechanistically novel carbonylative cycloaddition route for the construction of substituted phenols, through the formation of four new chemical bonds, with excellent functional‐group tolerance. [ABSTRACT FROM AUTHOR]

Abstract: A new palladium‐catalyzed reductive [5+1] cycloaddition of 3‐acetoxy‐1,4‐enynes with CO, enabled by hydrosilanes, has been developed for delivering valuable functionalized phenols. This methodology employs hydrosilanes as the external reagent to facilitate the [5+1] carbonylative benzannulation. The reaction is a conceptually and mechanistically novel carbonylative cycloaddition route for the construction of substituted phenols, through the formation of four new chemical bonds, with excellent functional‐group tolerance. [ABSTRACT FROM AUTHOR]

Abstract: α‐Carbonyl alkyl bromides are powerful reactive species for the formation of carbon–carbon bonds. Strategies relying on intermolecular C−H functionalization and cross‐coupling reactions, also referred to as intramolecular cyclization, have been employed for the construction of alkenes, alkanes, ketones, and other natural‐product‐like ring compounds from simple alkynes, alkenes, and 1,n‐enynes. In view of the importance of these α‐carbonyl alkyl bromides, especially the difluoro carbonyl alkyl bromides, many researchers have focused their efforts to develop facile and mild synthetic methods for compounds with important biological activities. This review aims to briefly discuss the latest developments in the transformation of α‐carbonyl alkyl bromides with emphasis on the related reaction mechanisms. [ABSTRACT FROM AUTHOR]

A copper-catalyzed oxidative radical strategy to avoid the use of the highly expensive noble metal/ligand catalytic systems is described, which allows selective activation of dual chemical bonds around the Si-atom center relying on the nature of alkylsilanes. While for tertiary silanes selective functionalization of Si–H/silyl C(sp3)–H bonds in intermolecular oxidative annulation cascades with N-(2-(ethynyl)aryl)acrylamides toward silino[3,4-c]quinolin-5(3H)-ones, when using secondary silanes and HSi(TMS)3, dual Si–H bonds or Si–H/Si–Si bonds are selectively cleaved leading to 4H-silolo[3,4-c]quinolin-4-ones. [ABSTRACT FROM AUTHOR]

A new palladium-catalyzed dearomatizative [2 + 2 + 1] carboannulation of 1,7-enynes with aryl diazonium salts and H2O is presented. The reaction enables the construction of spirocyclohexadienone-fused cyclopenta[c]quinolin-4(5H)-ones through a sequence of Heck-type addition, 6-exo-dig cyclization, ipso-cyclization, dearomatization and hydrolysis. [ABSTRACT FROM AUTHOR]

The first iron-catalyzed 1,2-difunctionalization of styrenes and conjugated alkenes with silanes and either N or C, using an oxidative radical strategy, is described. Employing FeCl2 and di- tert-butyl peroxide allows divergent alkene 1,2-difunctionalizations, including 1,2-aminosilylation, 1,2-arylsilylation, and 1,2-alkylsilylation, which rely on a wide range of nucleophiles, namely, amines, amides, indoles, pyrroles, and 1,3-dicarbonyls, thus providing a powerful platform for producing diverse silicon-containing alkanes. [ABSTRACT FROM AUTHOR]

The first iron-catalyzed 1,2-difunctionalization of styrenes and conjugated alkenes with silanes and either N or C, using an oxidative radical strategy, is described. Employing FeCl2 and di- tert-butyl peroxide allows divergent alkene 1,2-difunctionalizations, including 1,2-aminosilylation, 1,2-arylsilylation, and 1,2-alkylsilylation, which rely on a wide range of nucleophiles, namely, amines, amides, indoles, pyrroles, and 1,3-dicarbonyls, thus providing a powerful platform for producing diverse silicon-containing alkanes. [ABSTRACT FROM AUTHOR]

A new route to producing 3-alkyl spiro[4,5]trienones via nickel-promoted radical oxidative ipso-annulation of N-( p-methoxyaryl)propiolamides with α-carbonyl alkyl bromides using TBHP oxidant is described. The method allows the formation of three new C-C bonds through a sequence of oxidative C-Br bond cleavage, ipso-cyclization and dearomatization, and represents a new alkyne 1,2-difunctionalization to access to the construction of spiro[4,5]trienones. [ABSTRACT FROM AUTHOR]

A new FeCl3 and BF3⋅OEt2 co-catalyzed tandem hetero-[5+2] cycloaddition of 2-(2-aminoethyl)oxiranes with a wide range of alkynes, including terminal alkynes and alkyl-substituted internal alkynes is presented. This is the first example of rapid and facile production of diverse 2,3-dihydro-1 H-azepines through a sequence of epoxide ring-opening, annulation, and dehydroxylation with broad substrate scope and exquisite selectivity control. [ABSTRACT FROM AUTHOR]

A new FeCl3 and BF3⋅OEt2 co-catalyzed tandem hetero-[5+2] cycloaddition of 2-(2-aminoethyl)oxiranes with a wide range of alkynes, including terminal alkynes and alkyl-substituted internal alkynes is presented. This is the first example of rapid and facile production of diverse 2,3-dihydro-1 H-azepines through a sequence of epoxide ring-opening, annulation, and dehydroxylation with broad substrate scope and exquisite selectivity control. [ABSTRACT FROM AUTHOR]

We cover the achievements and thought process that have emerged as a result of the recent use of iron salts as catalysts for the oxidative coupling, addition, and functionalization on constructing C−C bonds, C−N bonds, C−O bonds, C−S bonds, and C−P bonds. These transformations concomitantly require a stoichiometric oxidant to activate the catalyst: The low-cost and ubiquity of peroxides is often used as a result of their high oxidative reactivity, resulting in the widespread utilizations of iron catalysis through the initiation of radical processes. Here, we summarize the formation of diverse chemical bonds by using iron oxidative catalysis strategies, including 1) the oxidative coupling strategy and 2) the oxidative addition and functionalization strategy. The oxidative coupling strategy focuses on the formation of one chemical bond in a single reaction, whereas the oxidative addition and functionalization strategy includes the transformations that construct at least two chemical bonds. [ABSTRACT FROM AUTHOR]

A new, metal-free, radical-mediated oxidative decarbonylative hydroalkylation of various alkynes with secondary and tertiary alkyl aldehydes using di- tert-butyl peroxide (DTBP) as oxidant is presented. This method enables the simultaneous formation of a CC bond and a CH bond through a sequence of decarbonylation, radical addition and protonation, and provides a straightforward route for transforming alkynes into alkenes with high compatibility with both alkynes and alkyl aldehydes. [ABSTRACT FROM AUTHOR]

The Cu-catalyzed oxidative [2+2+1] annulation of 1,n-enynes (n = 6, 7) with α-carbonyl alkyl bromides through C–Br/C–H functionalization has been developed. Using Ag2CO3/tert-butyl hydroperoxide (TBHP) as co-oxidants, α-carbonyl alkyl bromides provide two bonds, the α-C(sp3)–Br bonds and the α-C(sp3)–H bonds, to cyclize with the 1,n-enynes and Cu(MeCN)4PF6, thus forming three new C–C bonds and two rings in a single reaction. [ABSTRACT FROM AUTHOR]

A new iron-facilitated silver-mediated radical 1,2-alkylarylation of styrenes with α-carbonyl alkyl bromides and indoles is described, and two new C−C bonds were generated in a single step through a sequence of intermolecular C(sp3)−Br functionalization and C(sp2)−H functionalization across the alkenes. This method provides an efficient access to alkylated indoles with broad substrate scope and excellent selectivity. [ABSTRACT FROM AUTHOR]

A new iron-facilitated silver-mediated radical 1,2-alkylarylation of styrenes with α-carbonyl alkyl bromides and indoles is described, and two new C−C bonds were generated in a single step through a sequence of intermolecular C(sp3)−Br functionalization and C(sp2)−H functionalization across the alkenes. This method provides an efficient access to alkylated indoles with broad substrate scope and excellent selectivity. [ABSTRACT FROM AUTHOR]

A Cu-catalyzed oxidative ipso-annulation of activated alkynes with unactivated alkanes for the synthesis of 3-alkyl spiro[4,5]trienones is described. This method allows the formation of two carbon–carbon bonds and one carbon–oxygen bond in a single reaction through a sequence of C–H oxidative coupling, ipso-carbocyclization and dearomatization. [ABSTRACT FROM AUTHOR]

A metal-free radical-mediated [4+2] annulation of internal arylalkynes with tert-butyl nitrite (t-BuONO) is presented for the synthesis of benzo[e][1,2]oxazin-4-ones through the addition of t-BuONO across the CŽ≡C triple bond, hydration, isomerization and aromatic C(sp2)--H oxidation cascades. The 18O-labeling experiment shows that two oxygen atoms in the product system are from water. [ABSTRACT FROM AUTHOR]

A new metal-free tert-butyl hydroperoxide (TBHP)-mediated carbonyl C(sp2)–H oxidative alkynylation of aldehydes with ethynyl benziodoxolones (EBX) for the synthesis of ynones is described. This method is based on a carbonyl C(sp2)–H oxidative radical coupling process according to mechanistic studies, and provides a general route to the assembly of diverse ynones with a broad substrate scope and excellent functional-group compatibility. [ABSTRACT FROM AUTHOR]

We here describe a new palladium-catalyzed oxidative 6-exo-trig cyclization of 1,6-enynes at room temperature using tBuONO as an oxidant for the synthesis of 3-bicyclo[4.1.0]heptan-5-ones. This cascade strategy involves the hydration, cyclization and cyclopropanation sequence, and represents a new transition-metal-catalyzed oxidative cyclization of 1,6-enynes in a 6-exo-trig fashion. [ABSTRACT FROM AUTHOR]

A new metal-free radical 5- exo-dig cyclization of phenol-linked 1,6-enynes with O2, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), and tBuONO is described. With this general method, carbonylated benzofurans can be accessed through incorporation of two oxygen atoms into the product from O2 and TEMPO through dioxygen activation and oxidative cleavage of the NO bond, respectively. [ABSTRACT FROM AUTHOR]

A new metal-free radical 5- exo-dig cyclization of phenol-linked 1,6-enynes with O2, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), and tBuONO is described. With this general method, carbonylated benzofurans can be accessed through incorporation of two oxygen atoms into the product from O2 and TEMPO through dioxygen activation and oxidative cleavage of the NO bond, respectively. [ABSTRACT FROM AUTHOR]

Oxindoles are important heterocyclic compounds that are found in a wide range of pharmaceutical agents and natural products. A new oxidative tandem route to the assembly of 3-(2-oxoethyl)indolin-2-ones from N-arylacrylamides and alcohols has been established by using inexpensive and environmentally benign iron catalysts and peroxides. In the presence of Fe(OAc)2 and tert-butyl hydroperoxide, a variety of arylacrylamides underwent the oxidative 1,2-carboacylation reaction with alcohols to give the corresponding 3-(2-oxoethyl)indolin-2-ones in moderate to good yields. [ABSTRACT FROM AUTHOR]

A novel copper-catalyzed oxidative alkylation of α-amino carbonyl compounds with ethers has been established for the selective synthesis of α-etherized α-amino carbonyl compounds. This oxidative alkylation is achieved by dual C( sp3)H bond oxidative cross-coupling, and its scope is expanded to α-amino ketones, α-amino esters and α-amino amides. [ABSTRACT FROM AUTHOR]

A practical method for the synthesis of azepine derivatives, a typical seven-membered heterocyclic ring system, was developed and involves the use of hexafluoroantimonic acid to catalyze a formal [3+2+2] cycloaddition of aziridines with two alkynes. This method was applicable to two of the same or different terminal alkynes for the [3+2+2] cycloaddition with unactivated aziridines, and furnished the corresponding azepine derivatives in good yields with good levels of chemo- and regioselectivity. The mechanism was also discussed according to the results of the in situ HRMS and 1H NMR analysis. [ABSTRACT FROM AUTHOR]

A practical method for the synthesis of azepine derivatives, a typical seven-membered heterocyclic ring system, was developed and involves the use of hexafluoroantimonic acid to catalyze a formal [3+2+2] cycloaddition of aziridines with two alkynes. This method was applicable to two of the same or different terminal alkynes for the [3+2+2] cycloaddition with unactivated aziridines, and furnished the corresponding azepine derivatives in good yields with good levels of chemo- and regioselectivity. The mechanism was also discussed according to the results of the in situ HRMS and 1H NMR analysis. [ABSTRACT FROM AUTHOR]

Copper-catalyzed amidation of acids with formamides or acetamide for the selective synthesis of amides with the aid of 1,4-diazabicyclo[2.2.2]octane as the ligand and tert-butyl hydroperoxide as the oxidant is presented. This method is highly compatible with a wide range of acids, including alkyl acids, aryl acids, α,β-unsaturated acids, and amino acids. [ABSTRACT FROM AUTHOR]

An efficient copper-catalyzed α-aminoxylation of ketones with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) is presented for the synthesis of 2-aryloxy-1-aryl-2-(2,2,6,6-tetramethylpiperidin-1-yloxy)ethanones in moderate to excellent yields. It is noteworthy that the copper/iron (Cu/Fe) catalyst can be recovered and reused several times with high catalytic reactivity. [ABSTRACT FROM AUTHOR]

Silver forges the ring: A new and practical silver‐catalyzed [5+2] cycloaddition method has been developed for the synthesis of azepines through the formation of four new chemical bonds between a γ‐amino ketone and an alkyne in one step. This method provides a new hetero‐[5+2] cycloaddition strategy for the construction of seven‐membered ring systems. [ABSTRACT FROM AUTHOR]

Silber schmiedet den Ring: Eine Silber ‐ katalysierte [5+2] ‐ Cycloaddition zur Synthese von Azepin ‐ Derivaten wurde entwickelt. In nur einer Stufe werden vier neue Bindungen zwischen einem γ ‐ Aminoketon und einem Alkin aufgebaut. Diese Methode stellt somit eine neue Hetero ‐ [5+2] ‐ Cycloaddition zur Synthese von Heptacyclen dar. [ABSTRACT FROM AUTHOR]

A novel palladium-catalyzed CH oxidation of isoquinoline N-oxides has been developed for regioselectively synthesizing substituted isoquinolines. The method represents the first example of using dialkyl sulfoxides as the alkyl sources for the construction of 1-alkylated isoquinolines. Moreover, the regioselective halogenation of isoquinoline N-oxides is also successful using dihalo sulfoxides as the halide sources. [ABSTRACT FROM AUTHOR]

Abstract: A novel one-pot multicatalytic route for the synthesis of 3-methyleneindolin-2-ones has been developed involving sequential copper-catalyzed amination and palladium-catalyzed C–H functionalization processes. In the presence of CuI and Pd(OAc)2, a variety of propiolamides underwent the reaction with iodides to afford the corresponding 3-methyleneindolin-2-ones in moderate yields. [Copyright &y& Elsevier]

Abstract: A solvent-free copper/iron-catalyzed N-arylation of nitrogen-containing heterocycles with trimethoxysilanes method for the formation of C–N bonds has been developed. In the presence of Cu, FeCl3, TBAF, and air, a variety of nitrogen-containing heterocycles including imidazoles and triazoles were coupled with aryltrimethoxysilanes and vinyltrimethoxysilane to afford the corresponding products in moderate to excellent yields. It is noteworthy that the reaction is conducted under solvent-free and relatively low Cu/FeCl3 loadings conditions. [Copyright &y& Elsevier]

We here describe a new copper-catalyzed oxidative coupling of acids with alkanes for the selective synthesis of allylic esters and alkylalkenes. This method achieves multiple dehydrogenation and esterification, representing a new unactivated C(sp3)–H oxidative esterification of acids with common alkanes. [ABSTRACT FROM AUTHOR]

A new external oxidant-free electrochemical dehydrogenative cross-coupling of xanthenes and ketones for the preparation of functionalized 9-alkyl-9H-xanthenes was developed. This method enables the formation of a new C(sp3)–C(sp3) bond through release of H2 as the major byproduct at room temperature, and features mild conditions, high atom economy, excellent functional-group tolerance, scalability and facile applications in pharmaceutical chemistry. [ABSTRACT FROM AUTHOR]

We here describe a new, selective indium-promoted silver-mediated intermolecular oxidative 1,4-alkylarylation of 1,3-dienes with α-carbonyl alkyl bromides and N-heterocycles for producing functionalized N-heterocycles, which is characterized by its exquisitely controllable regio-/stereo-selectivity and excellent tolerance of functional groups. Mechanistically, the formation of the carbonyl-coordinated η3-allyl-In complex radical intermediate is the key factor for successfully achieving regio- and stereo-selectivity toward 1,4-difunctionalization and (E)-isomers. [ABSTRACT FROM AUTHOR]

An abstract of the article "(5 + 2) Cycloaddition of 2-(2-Aminoethyl)oxiranes with Alkynes via Epoxide Ring-Opening: A Facile Access to Azepines" by Yang Y., Li Jh, and Luo S. is presented.

An abstract of the article "[5 + 2] Cycloaddition of 2-(2-Aminoethyl)oxiranes with Alkynes via Epoxide Ring-Opening: A Facile Access to Azepines" by Chao Hu and colleagues is presented.

An abstract of the study "Metal-Free Oxidative 1,2-Arylmethylation Cascades of N-(Arylsulfonyl)acrylamides Using Peroxides as the Methyl Resource" by F. L. Tan and colleagues is presented.

The article presents chemical equations for the study "Metal-Free Oxidative Decarbonylative Hydroalkylation of Alkynes with Secondary and Tertiary Alkyl Aldehydes" by X. H. Ouyang and others published in "Advanced Synthesis and Catalysis" in 2016.

Review: [42 refs. [ABSTRACT FROM AUTHOR]

A highly para-selective amination of anilines with phenothiazines for producing various functionalized 10-aryl-10H-phenothiazines is reported. The oxidative amination reaction proceeds electrochemically at room temperature, thereby avoiding the use of metals and oxidizing reagents with excellent functional group tolerance and broad substrate scope. [ABSTRACT FROM AUTHOR]

A new ruthenium(ii)-catalyzed electrooxidative [4+2] annulation of primary benzylic alcohols with internal alkynes is described, which enables benzylic alcohols as weakly directing group precursors to access isocoumarins via multiple C–H functionalization. The reaction works well with a broad substrate scope, tolerates a wide range of functional groups, and incorporates practically the isocoumarin unit into diverse bioactive molecules. Mechanistic studies indicate that activation of aryl C(sp2)–H bonds is achieved through the generation of the active benzoyloxy–Ru(ii) intermediates via oxidation of benzylic alcohols using an electrooxidative Ru(ii) catalyst. [ABSTRACT FROM AUTHOR]

An indium-promoted intermolecular oxidative 1,2-alkylarylation of alkenes with alkyl nitriles and N-heteroarenes enabled by C(sp3)–H/C(sp2)–H functionalization is presented. This oxidative radical strategy allows the formation of two new C–C bonds through transformations of two different C–H bonds across the alkenes in a controlled single-step manner, and offers a general, highly atom-economic route for the production of new functionalized N-heteroarenes, including indoles, pyrrolo[2,3-b]pyridine, pyrrolo[3,2,1-ij]quinolone and pyrroles. [ABSTRACT FROM AUTHOR]

The new radical 1,2-alkylarylation of styrenes results in two new C-C bonds generated in a single step through a sequence of intermolecular C(sp3)-Br functionalization and C(sp2)-H functionalization across the alkene. [ABSTRACT FROM AUTHOR]

The Ag(I)-promoted oxidative [2 + 2 + 1]-annulation of enynes with activated alkyl bromides is achieved in the presence of Cu-catalyst to form three new C-C bonds and two rings in a single step. [ABSTRACT FROM AUTHOR]

An abstract of the article "Silver-Promoted Oxidative Ring Opening/Alkynylation of Cyclopropanols: Facile Synthesis of 4-Yn-1-ones," by C.-Y. Wang and colleagues is presented.

An abstract of the article "Synthesis of 3-Alkyl Spiro[4,5]trienones by Copper-Catalyzed Oxidative ipso-Annulation of Activated Alkynes with Unactivated Alkanes," by X.-H. Ouyang and colleagues is presented.

The article presents chemical equations related to the article "Copper-Catalyzed Radical [2 + 2 + 1] Annulation of Benzene-Linked 1,n-Enynes with Azide: Fused Pyrroline Compounds" by M. Hu and others, published in the "Organic Letters" in 2015.