Rhodium(III)-Catalyzed Ortho-Alkenylation through C–H Bond Cleavage Directed by Sulfoxide Groups

Recent developments in synthetic methods for benzo[b]heteroles

Benzo[b]heteroles containing heteroatoms other than nitrogen and oxygen have received considerable attention for their potential applications in materials science. This poses an increasing demand for efficient, selective, and broad-scope methods for their synthesis. This review article summarizes the recent developments in synthetic methods and approaches to access representative members of the benzoheterole family.

Silver-mediated oxidative annulation of N-arylthio succinimides with alkynes: direct access to benzo[b]thiophenes

A convenient synthetic route to 2,3-diarylbenzo[b]thiophene derivatives via Ag-catalyzed intermolecular oxidative cyclization between bench-stable N-arylthio succinimides and unactivated internal alkynes is demonstrated herein.

Visible light catalyzed methylsulfoxidation of (het)aryl diazonium salts using DMSO

The visible light catalyzed methylsulfoxidation of (het)aryl diazonium salts using DMSO is illustrated.

Sulfuration of the C(sp2)–H bond of enaminones: a protocol for the synthesis of thioether using elemental sulfur as a sulfurating reagent

Sulfuration reaction of the C(sp²)–H bond of enaminones with elemental sulfur in the presence of CuBr/K₃PO₄ was carried out. It provided an efficient method for the synthesis of thioethers and selenides in moderate to good yields.

Iron-mediated oxidative C–H coupling of arenes and alkenes directed by sulfur: an expedient route to dihydrobenzofurans

A route to medicinally-relevant dihydrobenzofurans utilises a sulfur-directed, iron-mediated C–H ortho-coupling of arenes and alkenes, and a palladium-catalysed heterocyclisation.

Highly selective synthesis of 6-substituted benzothiophenes by Sc(OTf)3-catalyzed intermolecular cyclization and sulfur migration

A series of 6-substituted benzo[b]thiophenes was synthesized using a Sc(OTf)₃-catalyzed intermolecular cyclization between para-substituted N-(arylthio)succinimides and alkynes taking advantage of a unique and selective 1,2-sulfur migration occuring via an electrophilic ipso cyclization to a key spirocyclic thiete intermediate.

Rhodium(iii)-catalyzed sp2 C–H bond addition to CF3-substituted unsaturated ketones

Rhodium(iii)-catalyzed conjugate addition of sp² C–H bonds to β-trifluoromethyl-α,β-unsaturated ketones was efficiently achieved.

RhI/RhIII catalyst-controlled divergent aryl/heteroaryl C-H bond functionalization of picolinamides with alkynes

The ability to establish switchable site-selectivity through catalyst control in the direct functionalization of molecules that contain distinct C-H bonds remains a demanding challenge that would enable the construction of diverse scaffolds from the same starting materials. Herein we describe the realization of this goal, namely a divergent heteroaryl/aryl C-H functionalization of aromatic picolinamide derivatives, targeting two distinct C-H sites, either at the pyridine ring or at the arene unit, to afford isoquinoline or ortho-olefinated benzylamine (or phenethylamine) derivatives. This complementary reactivity has been achieved on the basis of a RhIII/RhI switch in the catalyst, resulting in different mechanistic outcomes. Notably, a series of experimental and DFT mechanistic studies revealed important insights about the mechanism of the reaction and reasons behind the divergent regiochemical outcome.

The emergence of sulfoxides as efficient ligands in transition metal catalysis

Sulfoxides are capable of forming stable complexes with transition metals and there have been many comprehensive studies into their binding properties. However, the use of sulfoxides, particularly chiral sulfoxides, as ligands in transition metal catalysis is rather less well developed. This review aims to describe these catalytic studies and covers new developments that are showing very promising results and that have led to a renewed interest in this field.

One-pot cascade synthesis of N-methoxyisoquinolinediones via Rh(iii)-catalyzed carbenoid insertion C–H activation/cyclization

A mild and efficient method for one-pot synthesis of N-methoxyisoquinolinediones via Rh(iii)-catalyzed carbenoid insertion C–H activation/cyclization has been developed.

Ruthenium-catalyzed ortho alkenylation of aromatic nitriles with activated alkenes via C–H bond activation

The ruthenium-catalyzed ortho alkenylation of substituted aromatic and heteroaromatic nitriles with activated alkenes via C–H bond activation is described.

Iron-mediated C–H coupling of arenes and unactivated terminal alkenes directed by sulfur

A sulfur-directed Fe(iii)-mediated ortho C–H coupling of arenes with unactivated terminal alkenes gives products of regioselective alkene chloroarylation.

Rhodium(iii)-catalyzed C–H/C–C activation sequence: vinylcyclopropanes as versatile synthons in direct C–H allylation reactions

Succession of C–H activation and C–C activation was achieved by using a single rhodium(iii) catalyst.

Recent advances in the ruthenium-catalyzed hydroarylation of alkynes with aromatics: synthesis of trisubstituted alkenes

The hydroarylation of alkynes with amide, azole, carbamate, phosphine oxide, amine, acetyl, sulfoxide and sulphur substituted aromatics in the presence of a ruthenium catalyst via chelation-assisted C–H bond activation is discussed.

Thioether-directed acetoxylation of C(sp2)–H bonds of arenes by palladium catalysis

The palladium-catalyzed acetoxylation of aromatic C(sp²)–H bonds utilizing thioether as the directing group was developed.

Transition metal-catalyzed C–H bond functionalizations by the use of diverse directing groups

In this review, a summary of transition metal-catalyzed C–H activation by utilizing the functionalities as directing groups is presented.

Rh(iii)-catalyzed and alcohol-involved carbenoid C–H insertion into N-phenoxyacetamides using α-diazomalonates

Here a new, mild and efficient Rh(iii)-catalyzed and alcohol-involved carbenoid insertion (ortho-alkylation) intoN-phenoxyacetamides using α-diazomalonates has been developed.

Sulfone promoted Rh(iii)-catalyzed C–H activation and base assisted 1,5-H shift strategy for the construction of seven-membered rings

A sequence of Rh(iii)-catalyzed C–H cleavage, 1,5-H shift and intramolecular allene insertion was developed for the construction of seven-membered rings.

Rhodium-catalyzed hydroarylation of alkynes via tetrazole-directed C–H activation

A rhodium-catalyzed hydroarylation of alkynes with aryl tetrazoles through tetrazole-directed C–H activation was developed.

Versatile palladium-catalyzed C–H olefination of (hetero)arenes at room temperature

The room-temperature oxidative C–H/C–H cross-couplings between simple arenes and alkenes, coumarins or quinones have been reported by using a highly electrophilic palladium species [Pd(TFA)₂] as the catalyst and cheap (NH₄)₂S₂O₈ as the oxidant under air.

Controllable mono-/di-alkenylation of aryl alkyl thioethers tuned by oxidants via Pd-catalysis

Oxidant controlled selective C–H bond mono-alkenylation and di-alkenylation of biphenylthioethers to synthesize sulfoxide-olefin ligands with thioether as the directing group.

Ruthenium-catalyzed highly regio- and stereoselective hydroarylation of aromatic sulfoxides with alkynes via C–H bond activation

A ruthenium-catalyzed hydroarylation of aromatic sulfoxides with alkynes in the presence of AgSbF₆ and pivalic acid yielding trisubstituted alkenes is described.