James Sanderson

Ruthenium(II)biscarboxylate catalysis enabled selective C−C functionalizations by means of decarbamoylative C−C arylations. The versatility of the ruthenium(II) catalysis was reflected by widely applicable C−C arylations and C−C alkylations of aryl amides, as well as acids with modifiable pyrazoles, through facile organometallic C−C activation.

Amid the methods: Amide σ-C−C arylations were accomplished by versatile ruthenium(II) carboxylate decarbamoylative catalysis, which enabled decarboxylative ipso C−C alkylations by facile organometallic C−C cleavage. The method is versatile, robust, and mild, and mechanistic insights are discussed.

An inexpensive nickel(II) catalyst and a hydrosilane were used for the efficient reductive defunctionalization of aryl and heteroaryl esters through a decarbonylative pathway. This versatile method could be used for the removal of ester and amide functional groups from various organic molecules. Moreover, a scale-up experiment and a synthetic application based on the use of a removable carboxylic acid directing group highlight the usefulness of this reaction.

Now you see it… now you don't: An inexpensive nickel(II) catalyst and a hydrosilane were used for the efficient reductive defunctionalization of aryl and heteroaryl esters by a decarbonylative pathway (see scheme). This versatile method is suitable for the removal of ester and amide functional groups, including carbonyl directing groups, from a variety of organic molecules.

The first photosensitizer-free visible light-driven, gold-catalyzed C–C cross-couplings of arylboronic acids and aryldiazonium salts are reported. The reactions can be conducted under very mild conditions, using a catalytic amount of tris(4-trifluoromethyl)phosphinegold(I) chloride [(4-CF₃-C₆H₄)₃PAuCl] with methanol as the solvent allowing an alternative access to a variety of substituted biaryls in moderate to excellent yields with broad functional group tolerance.

The formation of the high-valent iron complex [Fe(cyclohexyl)₄] from Fe^II under reducing conditions is best explained by disproportionation of a transient organoiron intermediate which is driven by dispersive forces between the cyclohexyl ligands and the formation of short and strong Fe−C bonds. The (meta)stability of this diamagnetic complex (S=0) is striking if one considers that it has empty d-orbitals at its disposal and contains, at the same time, no less than twenty H-atoms available for either α- or β-hydride elimination.

Let's hold together: The homoleptic and diamagnetic Fe^IV complex [Fe(cyclohexyl)₄] is spontaneously formed under reductive conditions on treatment of FeX₂ (X=Cl, acac) with excess C₆H₁₁MgCl. This unorthodox species is (meta)stable, even though the high-valent metal center has three empty d-orbitals at its disposal and is surrounded by no less than 20 hydrogen atoms available for α- or β-hydride elimination.

The first example of a heterogeneous iron(III)-catalyzed aerobic oxidation of aldehydes in water was developed. This method utilizes 1 atmosphere of oxygen as the sole oxidant, proceeds under extremely mild aqueous conditions, and covers a wide range of various functionalized aldehydes. Chromatography is generally not necessary for product purification. Its operational simplicity, gram-scale oxidation, and the ability to successively reuse the catalyst, make this new methodology environmentally benign and cost effective. The generality of this methodology gives it the potential to be used on an industrial scale.

Ironclad: A heterogeneous aerobic oxidation of aldehydes in water was developed with a polyoxometalate-based iron catalyst. This method utilizes 1 atmosphere of oxygen as the sole oxidant, proceeds under extremely mild aqueous conditions, and covers a wide range of various functionalized aldehydes.

The replacement of noble metal technologies and the realization of new reactivities with earth-abundant metals is at the heart of sustainable synthesis. Alkene hydrogenations have so far been most effectively performed by noble metal catalysts. This study reports an iron-catalyzed hydrogenation protocol for tri- and tetra-substituted alkenes of unprecedented activity and scope under mild conditions (1–4 bar H₂, 20 °C). Instructive snapshots at the interface of homogeneous and heterogeneous iron catalysis were recorded by the isolation of novel Fe nanocluster architectures that act as catalyst reservoirs and soluble seeds of particle growth.

An iron-catalyzed hydrogenation has been developed based on the simple ternary catalyst system Fe[N(SiMe₃)₂]₂/iBu₂AlH. Clean hydrogenations of challenging alkenes proceeded under very mild conditions (1–4 bar H₂, 20 °C). The simple mixing of the ferrous salt, reductant, and ligand is particularly user-friendly. Isolation of soluble Fe nanoclusters provides insight into reductive catalyst formation and nanoparticle aggregation.

The discovery of an ultrafast cross-coupling of alkyl- and aryllithium reagents with a range of aryl bromides is presented. The essential role of molecular oxygen to form the active palladium catalyst was established; palladium nanoparticles that are highly active in cross-coupling reactions with reaction times ranging from 5 s to 5 min are thus generated in situ. High selectivities were observed for a range of heterocycles and functional groups as well as for an expanded scope of organolithium reagents. The applicability of this method was showcased by the synthesis of the [¹¹C]-labeled PET tracer celecoxib.

No oxygen, no coupling: Molecular oxygen was shown to be crucial for the fast palladium-catalyzed cross-coupling of organolithium reagents developed herein. Reactions times down to 5 s provide a novel procedure for the preparation of radiolabeled compounds.

Suzuki, Negishi, and Kumada couplings are some of the most important reactions for the formation of skeletal C−C linkages. Their widespread use to forge bonds between two aromatic rings has enabled every branch of chemical science. The analogous union between alkyl halides and metallated aryl systems has not been as widely employed due to the lack of commercially available halide building blocks. Redox-active esters have recently emerged as useful surrogates for alkyl halides in cross-coupling chemistry. Such esters are easily accessible through reactions between ubiquitous carboxylic acids and coupling agents widely used in amide bond formation. This article features an amalgamation of in-house experience bolstered by approximately 200 systematically designed experiments to accelerate the selection of ideal reaction conditions and activating agents for the cross-coupling of primary, secondary, and tertiary alkyl carboxylic acids with both aryl and heteroaryl organometallic species.

Cross-coupling meets amide bond formation: Decarboxylative cross-coupling with redox-active esters forms C−C bonds using boronic acids, organozinc, and organomagnesium species with simplicity comparable to amide bond formation. The extensive study enables selection of optimal activating agents and conditions across various substrates, including notoriously challenging heteroarenes.

The atom-economic and one-pot regio- and stereoselective addition of sodium arenesulfinates to either alkynes or alkenes can be achieved with an iron(III) chloride hexahydrate [FeCl₃⋅6 H₂O] catalytic system to afford β-haloalkenyl and β-chloroalkyl sulfones in moderate to good yields.