Cobalt-Catalyzed, Aminoquinoline-Directed Coupling of sp² C–H Bonds with Alkenes

A method for cobalt-catalyzed, aminoquinoline-directed <i>ortho</i>-functionalization of sp² C–H bonds with alkenes has been developed. Reactions proceed at room temperature in trifluoroethanol solvent, use oxygen from air as an oxidant, and require Mn­(OAc)₃ as a cocatalyst. Benzoic, heteroaromatic, and acrylic acid aminoquinoline amides react with ethylene as well as mono- and disubstituted alkenes affording products in good yields. Excellent functional group tolerance is observed; halogen, nitro, ether, and unprotected alcohol functionalities are compatible with the reaction conditions

Silylaryl Halides Can Replace Triflates as Aryne Precursors

Silylaryl bromides and iodides can be prepared in one step from commercially available starting materials. Arynes can be generated from these compounds under conditions nearly identical to those employed for silylaryl triflates. Three distinct transformations, ortho-arylation of <i>N</i>-tritylanilines, intermolecular addition of arynes to amides, and reaction of ureas with arynes, were shown to be successful for the new aryne precursors. The main advantage of silylaryl halides relative to silyl aryl triflates is their one-step preparation from commercially available starting materials

Cobalt-Promoted Dimerization of Aminoquinoline Benzamides

A method for aminoquinoline-directed, cobalt-promoted dimerization of benzamides has been developed. Reactions proceed in ethanol solvent in the presence of Mn­(OAc)₂ cocatalyst and Na₂CO₃ base and use oxygen as a terminal oxidant. Bromo, iodo, nitro, ether, and ester moieties are compatible with the reaction conditions. Cross-coupling of electronically dissimilar aminoquinoline benzamides proceeds with modest yields and selectivities

Cobalt-Catalyzed Direct Carbonylation of Aminoquinoline Benzamides

A method for direct carbonylation of aminoquinoline benzamides has been developed. Reactions proceed at room temperature in trifluoroethanol solvent, use oxygen from air as an oxidant, and require Mn­(OAc)₃ as a cocatalyst. Benzoic and acrylic acid derivatives can be carbonylated by carbon monoxide affording imides in good yields. Halogen, nitro, ether, cyano, and ester functional groups are tolerated. The directing group can be removed under mild conditions affording phthalimides

A General Method for Aminoquinoline-Directed, Copper-Catalyzed sp² C–H Bond Amination

An operationally simple and general method for copper-catalyzed, aminoquinoline-assisted amination of β-C­(sp²)-H bonds of benzoic acid derivatives is reported. The reaction employs Cu­(OAc)₂ or (CuOH)₂CO₃ catalysts, an amine coupling partner, and oxygen from air as a terminal oxidant. Exceptionally high generality with respect to amine coupling partners is observed. Specifically, primary and secondary aliphatic and aromatic amines, heterocycles, such as indoles, pyrazole, and carbazole, sulfonamides, as well as electron-deficient aromatic and heteroaromatic amines are competent coupling components

Copper-Catalyzed Etherification of Arene C–H Bonds

A method for direct, auxiliary-assisted alkoxylation and phenoxylation of β-sp² C–H bonds of benzoic acid derivatives and γ-sp² C–H bonds of amine derivatives is reported. The reaction employs (CuOH)₂CO₃ catalyst, air as an oxidant, phenol or alcohol coupling partner, DMF, pyridine, or DMPU solvent, and K₂CO₃, tetramethylguanidine, or K₃PO₄ base at 70–130 °C

Direct Intermolecular Aniline <i>Ortho-</i>Arylation via Benzyne Intermediates

A method for direct, transition-metal-free <i>ortho</i>-arylation of anilines by aryl chlorides, bromides, fluorides, and triflates has been developed. This methodology provides the most direct approach to 2-arylanilines since no protecting or directing groups on nitrogen are required. The arylation is functional-group tolerant, with alkene, ether, trifluoromethyl, dimethylamino, carbonyl, chloro, and cyano functionalities tolerated. Phenylation of enantiopure binaphthyldiamine affords a product with >99% ee

Synthesis of 1,2-Bis(trifluoromethylthio)arenes via Aryne Intermediates

A general method for synthesis of 1,2-bis-trifluoro­methyl­thioarenes has been developed. Arynes generated from silyl aryl triflates or halides react with bis­(trifluoro­methyl)­disulfide to afford 1,2-bis-trifluoro­methyl­thioarenes. Aryl, alkyl, ester, halide, and methoxy functionalities are compatible with reaction conditions. Use of bis­(perfluoroaryl)­disulfides gave moderate yields of aryne disulfenylation or cyclization to fluorinated dibenzothiophenes

Copper-Catalyzed Carboxylation of Aryl Iodides with Carbon Dioxide

A method for carboxylation of aryl iodides with carbon dioxide has been developed. The reaction employs low loadings of copper iodide/<i>N,N,N</i>′<i>,N</i>′-tetramethyl­ethylene­diamine (TMEDA) or <i>N,N</i>′-dimethyl­ethylene­diamine (DMEDA) catalyst, 1 atm of CO₂, dimethylsulfoxide (DMSO) or dimethylacetamide (DMA) solvent, and proceeds at 25–70 °C. Good functional group tolerance is observed, with ester, bromide, chloride, fluoride, ether, hydroxy, amino, and ketone functionalities tolerated. Additionally, hindered aryl iodides such as iodomesitylene can also be carboxylate

Heterocycle Synthesis via Direct C–H/N–H Coupling

A method for five- and six-membered heterocycle formation by palladium-catalyzed C–H/N–H coupling is presented. The method employs a picolinamide directing group, PhI­(OAc)₂ oxidant, and toluene solvent at 80–120 °C. Cyclization is effective for sp² as well as aliphatic and benzylic sp³ C–H bonds