Computational Exploration of 1,2-Carboamine Carbonylation Catalyzed by Nickel

Nickel-catalyzed carbonylation of alkenes is a stereoselective and regioselective method for the synthesis of amide compounds. Theoretical predictions with density functional theory calculations revealed the mechanism and origin of stereoselectivity and regioselectivity for the nickel-catalyzed carbonylation of norbornene. The carbonylation reaction proceeds through oxidative addition, migration insertion of alkenes, and subsequent reduction elimination to afford cis-carbonylation product. The C-N bond activation of amides is unfavorable because the oxidative addition ability of the C-C bond is stronger than that of the C-N bond. The determining step of stereoselectivity is the migratory insertion of the strained olefin. The structural analysis shows that steroselectivity is controlled by the steric hindrance of methyl groups to olefins and substituents to IMes in ligands.

Decarbonylative cycloaddition of 1H-indene-1,2,3-trione and norbornene via rhodium(i)-catalyzed carbon–carbon bond cleavage

2,3-Dihydro-1H-inden-1-one derivatives were synthesized by a [5+2−2] decarbonylative cycloaddition of 1H-indene-1,2,3-trione and norbornene via rhodium(i) catalyzed direct carbon–carbon bond cleavage.

Organic synthesis with the most abundant transition metal–iron: from rust to multitasking catalysts

The promising aspects of iron in synthetic chemistry are being explored for three-four decades as a green and eco-friendly alternative to late transition metals. This present review unveils these rich iron-chemistry towards different transformations.

Recent progress in C(aryl)–C(alkyl) bond cleavage of alkylarenes

Cleavage of the C(aryl)–C(alkyl) σ-bond is important both in academy and industry as it holds the potential to provide straightforward access to a variety of targets from readily available chemical feedstocks such like alkylarenes.

Iron-catalyzed oxidative C–C(vinyl) σ-bond cleavage of allylarenes to aryl aldehydes at room temperature with ambient air

The iron-catalyzed C−C single bond cleavage and oxidation of allylarenes without the assistance of heteroatoms/directing groups to produce aryl aldehydes is disclosed.

The molecular mechanism of palladium-catalysed cyanoesterification of methyl cyanoformate onto norbornene

Potential energy surface mapping was completed for the entire catalytic cycle of palladium-catalysed cyanoesterification onto norbornene (NBE) using density functional theory calculations. We found that after the oxidative addition step of the reagent methyl cyanoformate, the reaction proceeds through an insertion of olefin into a Pd(II)-COOMe bond first. Subsequently, reductive elimination occurs by transferring the cyanide group from the Pd center to NBE. This rearrangement is triggered by the rotation of the ester group into a π-interaction with the Pd(II) centre. The regioselectivity of olefin insertion is controlled by ionic and covalent interactions in the precursor π-complex formation step. Importantly, all of the intermediates and transition states along the exo pathway were found to be more stable than the corresponding structures of the endo pathway without any sign of crossing over between the two surfaces via isomerization. The rate-determining step is the reductive elimination despite the fact that the corresponding activation barrier is reduced by conformational changes via the rotation of a MeOOC-C(NBE) bond.

Iron-catalyzed aerobic oxidative cleavage of the C–C σ-bond using air as the oxidant: chemoselective synthesis of carbon chain-shortened aldehydes, ketones and 1,2-dicarbonyl compounds

An efficient iron-catalyzed aerobic oxidative cleavage of the C–C bond to generate a number of carbon-shortened carbonyl compounds.

Subtle effects of ligand backbone on the efficiency of iron-diphos catalysed Negishi cross-coupling reactions

Readily available and modifiable diphosphines with a thiophene backbone produce more efficient iron catalysts for Negishi cross-coupling than analogues with a phenylene backbone.

Methanol tolerant, high performance, noble metal free electrocatalyst developed from polyaniline and ferric chloride for the oxygen reduction reaction

Here, we report a low-cost, noble metal free Fe–N–C catalyst prepared using carbonized polyaniline (PANI) and ferric chloride as precursors in an inert atmosphere for oxygen reduction reaction.

Iron-catalyzed aerobic oxidative functionalization of sp3 C–H bonds: a versatile strategy for the construction of N-heterocycles

Iron-catalyzed aerobic oxidative functionalization of sp³ C–H bonds using a biofriendly iron catalyst in combination with O₂ or air as the sole oxidant has been developed for the construction of N-heterocycles from easily available carboxylic acid derivatives and o-substituted anilines.

Direct activation of relatively unstrained carbon-carbon bonds in homogeneous systems

New modes of chemical reactivity are of high value to synthetic organic chemistry. In this vein, carbon-carbon (C-C) activation is an emerging field that offers new possibilities for synthesizing valuable complex molecules. This review discusses the pioneering stoichiometric discoveries in this field up to the most recent synthetic applications that apply catalytic transformations. Specifically, the review focuses on C-C activation in relatively unstrained systems, including stoichiometric reactions, chelation-directed and chelation-free catalytic reactions. While the field of C-C activation of relatively unstrained systems is underdeveloped, we expect that this review will provide insight into new developments and pave the path for robust, practical applications.

Fe or Fe-NO catalysis? A quantum chemical investigation of the [Fe(CO)3(NO)](-)-catalyzed Cloke-Wilson rearrangement

A quantum chemical investigation of the Bu4N[Fe(CO)3(NO)]-catalyzed Cloke-Wilson rearrangement of vinyl cyclopropanes is reported. It was found that allylic C-C bond activation can proceed through a SN2' or SN2-type mechanism. The application of the recently reported intrinsic bond orbital (IBO) method for all structures indicated that one Fe-N π bond is directly involved. Further analysis showed that during the reaction oxidation occurs at the NO ligand exclusively.

Spectroelectrochemical investigation of Bu4N[Fe(CO)3(NO)]: identification of a reversible EC-mechanism

Bu4N[Fe(CO)3(NO)] displays unique catalytic properties in electron-transfer catalysis such as in allylic substitutions, hydrosilylation, transesterifications, or carbene transfer chemistry. Herein we present a detailed spectroelectrochemical investigation of this complex that unravels an interesting electrochemical-chemical transformation in which two parts of [Fe(CO)3(NO)](-) are oxidized and undergo a disproportionation in the presence of CO to [Fe(CO)5] and [Fe(CO)2(NO)2]. Upon re-reduction the former two complexes regenerate [Fe(CO)3(NO)](-) to about 85%.

Iron-catalyzed/mediated oxidative transformation of C–H bonds

Iron-catalyzed/mediated C–H bond oxidation has been demonstrated as one of practical and straightforward tools in synthetic chemistry.