The cross-dehydrogenative coupling of C(sp3)-H bonds: a versatile strategy for C-C bond formations

Copper-catalyzed oxidative oxyalkylation of enol ethers with α-amino carbonyl compounds and hydroperoxides

The first example of alkene oxyalkylation through C(sp³)–H functionalization is described for the synthesis of 2-amino-3,4-dioxy carbonyl compounds.

Rhenium-catalysed dehydrogenative borylation of primary and secondary C(sp3)–H bonds adjacent to a nitrogen atom

A novel rhenium-catalyzed borylation of C(sp³)–H bonds proceeded in the absence of oxidants, hydrogen acceptors, and external ligands with the generation of H₂ as the sole byproduct.

Directing-group-assisted copper-catalyzed oxidative esterification of phenols with aldehydes

A directing-group-assisted copper-catalyzed oxidative esterification of phenols with aldehydes using TBHP as an oxidant was described.

Sulphur promoted C(sp3)–C(sp2) cross dehydrogenative cyclisation of acetophenone hydrazones with aldehydes: efficient synthesis of 3,4,5-trisubstituted 1H-pyrazoles

The first-time sulfur-promoted CDC approach involving acetophenone hydrazones and aldehydes has been developed for the synthesis of substituted pyrazoles.

Peroxide promoted tunable decarboxylative alkylation of cinnamic acids to form alkenes or ketones under metal-free conditions

In the presence of DTBP or DTBP/TBHP, the decarboxylative alkylation of cinnamic acids with alkanes gave alkenes and ketones respectively via a radical mechanism in moderate to good yields.

Pd-catalyzed direct C2-acylation and C2,C7-diacylation of indoles: pyrimidine as an easily removable C–H directing group

Pyrimidine is successfully used as an easily removable C(sp²)–H directing group for the synthesis of 2-acyl indoles using a Pd-catalyst.

Pd/Cu-cocatalyzed reigoselective arylation of thiazole derivatives at 2-position under ligand-free conditions

An efficient protocol for regioselective arylation of thiazole derivatives at the 2-position via palladium- and copper-catalyzed C–H bond activation under ligand-free conditions has been developed.

Silver catalysed decarboxylative alkylation and acylation of pyrimidines in aqueous media

Decarboxylative alkylation or acylation reactions of simple pyrimidines have been developed in aqueous media.

Cu-catalyzed oxidative Povarov reactions between N-alkyl N-methylanilines and saturated oxa- and thiacycles

Cu-catalyzed oxidative Povarov reactions between N,N-dialkylanilines and saturated oxa- or thiacycles with tert-butyl hydroperoxide (TBHP) are described.

Ligand-promoted intramolecular dehydrogenative cross-coupling using a Cu catalyst: direct access to polycyclic heteroarenes

A copper(ii)-promoted intramolecular C–H coupling reaction between indole-2 and imidazole-2 moieties, which provides direct access to biheteroaryl incorporated polycyclic frameworks.

A facile approach to synthesize 3,5-disubstituted-1,2,4-oxadiazoles via copper-catalyzed-cascade annulation of amidines and methylarenes

A tandem Cu-catalyzed oxidation–amination–cyclization reaction for synthesizing various 3,5-disubstituted-1,2,4-oxadiazoles from easily available amidines and methylarenes or methylhetarenes is reported.

The direct α-C(sp3)–H functionalisation of N-aryl tetrahydroisoquinolines via an iron-catalysed aerobic nitro-Mannich reaction and continuous flow processing

An efficient nitro-Mannich type direct α-C(sp³)–H functionalisation of N-aryl-1,2,3,4-tetrahydroisoquinolines catalysed by simple iron salts in combination with O₂ as the terminal oxidant is described.

Utilization of methylarenes as versatile building blocks in organic synthesis

This review attempts to describe the latest developments in the utilisation of methylarenes adopting C–H functionalization strategies and covers all the developments until March 2015.

Oxidative C–S bond cleavage reaction of DMSO for C–N and C–C bond formation: new Mannich-type reaction for β-amino ketones

A novel oxidative C–S bond cleavage reaction of DMSO for N-methylation and subsequent C–C bond formation is described.

Tuning radical reactivity using iodine in oxidative C(sp3)–H/C(sp)–H cross-coupling: an easy way toward the synthesis of furans and indolizines

Molecular iodine was found to be an effective redox catalyst for the oxidative cross-coupling of carbonyl compounds with terminal alkynes.

Ni(ii)-catalyzed dehydrative alkynylation of unactivated (hetero)aryl C–H bonds using oxygen: a user-friendly approach

Ni(ii)-catalyzed dehydrative alkynylation of unactivated C(sp²)–H bonds with terminal alkynes under atmospheric pressure of oxygen is described.

C1-Benzyl and benzoyl isoquinoline synthesis through direct oxidative cross-dehydrogenative coupling with methyl arenes

An oxidative cross-dehydrogenative coupling of isoquinolines with methyl arenes has been developed, yielding structurally diverse C₁-benzyl and -benzoyl isoquinolines selectively. The direct use of readily available methyl arenes as coupling partners avoids unproductive steps for preactivating functional group installation, and is thereby attractive.

NIS-mediated intramolecular oxidative α-functionalization of tertiary amines: transition metal-free synthesis of 1,2-dihydro-(4H)-3,1-benzoxazin-4-one derivatives

A novel method for direct α-functionalization of tertiary amines via NIS-mediated oxidative C–O bond formation, where NIS serves as both an oxidant and an iodination reagent, has been developed.

Iron-catalyzed direct α-arylation of ethers with azoles

The direct α-arylation of cyclic and acyclic ethers with azoles has been achieved, which features a novel iron-catalyzed cross-dehydrogenative coupling (CDC) process.

Pd-Catalyzed direct C–H functionalization of imidazolones with aryl- and alkenyl halides

Direct C–H arylation and alkenylation of 4,4′-dialkylimidazolones with a broad range of halides under palladium and copper catalysis have been developed.

Copper-catalyzed oxidative coupling of acids with alkanes involving dehydrogenation: facile access to allylic esters and alkylalkenes

A new copper-catalyzed oxidative coupling of acids with alkanes for selective synthesis of allylic esters and alkylalkenes is described.

TBHP/TFA mediated oxidative cross-dehydrogenative coupling of N-heterocycles with aldehydes

A metal-free oxidative cross-dehydrogenative coupling of N-heterocycles with diverse aldehydes has been established in the presence of TBHP/TFA.

Highly efficient heterogeneous aerobic cross-dehydrogenative coupling via C–H functionalization of tertiary amines using a nanoporous gold skeleton catalyst

We disclosed that zero-valent nanoporous gold (AuNPore) possesses remarkable catalytic activity and reusability for heterogeneous aerobic cross-dehydrogenative coupling (CDC) of various tertiary amines with nucleophiles.

Direct regioselective oxidative cross-coupling of indoles with methyl ketones: a novel route to C3-dicarbonylation of indoles

The first C3-dicarbonylation of indoles was realized through direct oxidative cross-coupling of indoles with methyl ketones in the presence of molecular iodine and pyrrolidine. This reaction constructed a highly efficient indolyl diketones scaffold, which might be regarded as a useful biological and pharmacological tool in the exploration of therapeutic A2BAR modulators. The use of inexpensive molecular iodine and pyrrolidine and a broad substrate scope make this protocol very practical. Preliminary mechanistic studies indicate that two paths are involved in this process.

Silver-Mediated Synthesis of Indolizines via Oxidative C-H functionalization and 5- endo-dig cyclization

An efficient strategy for the synthesis of indolizines from readily available starting materials via oxidative C-H functionalization and 5-endo-dig cyclization in one step has been demonstrated. This protocol represents wide substrate scope, high functional group tolerance and selectivity. The structure of the product was confirmed by the X-ray crystallographic studies. The Ag₂CO₃ required of this tandem reaction can be recycled and reused after undergoing oxidative reaction.

Intramolecular [3 + 2]-cycloadditions of azomethine ylides derived from secondary amines via redox-neutral C-H functionalization

Azomethine ylides are accessed under mild conditions via benzoic acid catalyzed condensations of 1,2,3,4-tetrahydroisoquinolines or tryptolines with aldehydes bearing a pendent dipolarophile. These intermediates undergo intramolecular [3 + 2]-cycloadditions in a highly diastereoselective fashion to form polycyclic amines with four new stereogenic centers. Challenging substrates such as piperidine, morpholine, and thiomorpholine undergo the corresponding reactions at elevated temperatures.

Structurally diverse α-substituted benzopyran synthesis through a practical metal-free C(sp3)-H functionalization

A trityl ion-mediated practical C-H functionalization of a variety of benzopyrans with a wide range of nucleophiles (organoboranes and C-H molecules) at ambient temperature has been disclosed. The metal-free reaction has an excellent functional group tolerance and high chemoselectivity and displays a broad scope with respect to both benzopyran and nucleophile partners, efficiently affording a collection of benzopyrans bearing diverse skeletons and α-functionalities in one step.

Efficient merging of copper and photoredox catalysis for the asymmetric cross-dehydrogenative-coupling of alkynes and tetrahydroisoquinolines

A highly efficient catalytic asymmetric alkynylation of prochiral CH2 groups in tetrahydroisoquinoline was developed using copper catalyzed cross-dehydrogenative-coupling of sp(3) and sp C-H bonds with the assistance of a photocatalyst and visible light.

Dehydrative C-H/N-OH functionalizations in H2O by ruthenium(II) catalysis: subtle effect of carboxylate ligands and mechanistic insight

A ruthenium(II) complex derived from the electron-deficient aromatic carboxylic acid 3-(F3C)C6H4CO2H proved to be a highly efficient catalyst for dehydrative alkyne annulation by NH-free hydroxamic acids in water. The C-H/N-OH functionalization occurred with excellent positional selectivity as well as ample substrate scope, setting the stage for effective intermolecular alkenylations of hydroxamic acids. Detailed mechanistic studies were suggestive of a kinetically relevant C-H metalation by carboxylate assistance along with subsequent migratory alkyne insertion, reductive elimination, and intramolecular oxidative addition.