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N-Iminopyridinium ylides are competent monodentate directing groups for cobalt-catalysed annulation of sp2 C–H bonds with internal alkynes. The pyridine moiety in the ylide serves as an internal oxidant and is cleaved during the reaction. The annulation reactions possess excellent compatibility with heterocyclic substrates, tolerating furan, thiophene, pyridine, pyrrole, pyrazole, and indole functionalities. [ABSTRACT FROM AUTHOR]

Abstract: A method for cobalt‐catalyzed, carboxylate‐directed functionalization of arene C−H bonds is reported. Alkynes, styrenes, and 1,3‐dienes can be coupled with benzoic acids to provide cyclic products in good yields. The reactions proceed in the presence of a cobalt(II) hexafluoroacetylacetonate catalyst, (TMS)2NH base, Ce(SO4)2 cooxidant, and oxygen oxidant. [ABSTRACT FROM AUTHOR]

Conspectus: In recent years, carbon-hydrogen bond functionalization has evolved from an organometallic curiosity to a tool used in mainstream applications in the synthesis of complex natural products and drugs. The use of C-H bonds as a transformable functional group is advantageous because these bonds are the most abundant functionality in organic molecules. One-step conversion of these bonds to the desired functionality shortens synthetic pathways, saving reagents, solvents, and labor. Less chemical waste is generated as well, showing that this chemistry is environmentally beneficial. This Account describes the development and use of bidentate, monoanionic auxiliaries for transition-metal-catalyzed C-H bond functionalization reactions. The chemistry was initially developed to overcome the limitations with palladium-catalyzed C-H bond functionalization assisted by monodentate directing groups. By the use of electron-rich bidentate directing groups, functionalization of unactivated sp³ C-H bonds under palladium catalysis has been developed. Furthermore, a number of abundant base-metal complexes catalyze functionalization of sp² C-H bonds. At this point, aminoquinoline, picolinic acid, and related compounds are among the most used and versatile directing moieties in C-H bond functionalization chemistry. These groups facilitate catalytic functionalization of sp² and sp³ C-H bonds by iron, cobalt, nickel, copper, ruthenium, rhodium, and palladium complexes. Exceptionally general reactivity is observed, enabling, among other transformations, direct arylation, alkylation, fluorination, sulfenylation, amination, etherification, carbonylation, and alkenylation of carbon-hydrogen bonds. The versatility of these auxilaries can be attributed to the following factors. First, they are capable of stabilizing high oxidation states of transition metals, thereby facilitating the C-H bond functionalization step. Second, the directing groups can be removed, enabling their use in synthesis and functionalization of natural products and medicinally relevant substances. While the development of these directing groups presents a significant advance, several limitations of this methodology are apparent. The use of expensive second-row transition metal catalysts is still required for efficient sp³ C-H bond functionalization. Furthermore, the need to install and subsequently remove the relatively expensive directing group is a disadvantage. [ABSTRACT FROM AUTHOR]

A method for cobalt-catalyzed, aminoquinoline- and picolinamide-directed C(sp2)H bond alkenylation by alkynes was developed. The method shows excellent functional-group tolerance and both internal and terminal alkynes are competent substrates for the coupling. The reaction employs a Co(OAc)2⋅4 H2O catalyst, Mn(OAc)2 co-catalyst, and oxygen (from air) as a terminal oxidant. [ABSTRACT FROM AUTHOR]

A methodfor cobalt-catalyzed, aminoquinoline-directed ortho-functionalization of sp2C–H bondswith alkenes has been developed. Reactions proceed at room temperaturein trifluoroethanol solvent, use oxygen from air as an oxidant, andrequire Mn(OAc)3as a cocatalyst. Benzoic, heteroaromatic,and acrylic acid aminoquinoline amides react with ethylene as wellas mono- and disubstituted alkenes affording products in good yields.Excellent functional group tolerance is observed; halogen, nitro,ether, and unprotected alcohol functionalities are compatible withthe reaction conditions. [ABSTRACT FROM AUTHOR]

We report a method for cobalt-catalyzed, aminoquinoline-directed sp2 C–H bond carbonylation of sulfonamides. The reactions proceed in a dichloroethane solvent, and employ diisopropyl azodicarboxylate as a carbon monoxide source, Mn(OAc)2 as a cooxidant and potassium pivalate as a base. Halogen, ester, and amide functionalities are compatible with the reaction conditions. This method allows for a short and efficient synthesis of saccharin derivatives. [ABSTRACT FROM AUTHOR]

A method for direct, auxiliary-assisted alkoxylation and phenoxylation of β-sp2C–H bonds of benzoic acid derivatives and γ-sp2C–H bonds of amine derivatives is reported. The reaction employs (CuOH)2CO3catalyst, air as an oxidant, phenol or alcohol coupling partner, DMF, pyridine, or DMPU solvent, and K2CO3, tetramethylguanidine, or K3PO4base at 70–130 °C. [ABSTRACT FROM AUTHOR]

Amin trifft Aren: Ein Verfahren zur direkten Aminierung von β ‐ sp2 ‐ C ‐ H ‐ Bindungen in Benzoesäuren und γ ‐ sp2 ‐ C ‐ H ‐ Bindungen in Benzylaminen wurde entwickelt. Die Reaktion wird von Cu(OAc)2 und einem Ag2CO3 ‐ Cokatalysator katalysiert, ist sehr allgemein anwendbar, toleriert viele funktionelle Gruppen und bietet einen einfachen Zugang zu ortho ‐ Aminobenzoesäurederivaten. [ABSTRACT FROM AUTHOR]

We have developed a method for direct, copper-catalyzed, auxiliary-assisted fluorination of β-sp2 C-H bonds of benzoic acid derivatives and γ-sp2 C-H bonds of a,a-disubstituted benzylamine derivatives. The reaction employs a CuI catalyst, a AgF fluoride source, and DMF, pyridine, or DMPU solvent at moderately elevated temperatures. Selective mono- or difluorination can be achieved by simply changing reaction conditions. The method shows excellent functional group tolerance and provides a straightforward way for the preparation of ortho-fluorinated benzoic acids. [ABSTRACT FROM AUTHOR]

A method for direct, copper-catalyzed, auxiliary-assisted fluorination of β-sp2 C-H bonds of benzoic acid derivatives and γ-sp2 C-H bonds of α,α-disubstituted benzylamine derivatives, respectively is developed. [ABSTRACT FROM AUTHOR]

Direct arylation and alkylation of amine and carboxylic acid derivatives is achieved with different aryl and alkyl iodides as well as benzyl and allyl bromides in the presence of a palladium catalyst. [ABSTRACT FROM AUTHOR]