Mechanochemical solid state single electron transfer from reduced organic hydrocarbon for catalytic aryl-halide bond activation.

Solid-state radical generation is an attractive but underutilized methodology in the catalytic strong bond activation process, such as the aryl-halide bond. Traditionally, such a process of strong bond activation relied upon the use of transition metal complexes or strongly reducing photocatalysts in organic solvents. The generation of the aryl radical from aryl halides in the absence of transition-metal or external stimuli, such as light or cathodic current, remains an elusive process.

Mesoionic N-heterocyclic olefin catalysed reductive functionalization of CO for consecutive -methylation of amines.

A mesoionic N-heterocyclic olefin (mNHO) was introduced as a metal-free catalyst for the reductive functionalization of CO leading to consecutive double -methylation of primary amines in the presence of 9-borabicyclo[3.3.1]nonane (9-BBN).

Mimicking transition metals in borrowing hydrogen from alcohols.

Borrowing hydrogen from alcohols, storing it on a catalyst and subsequent transfer of the hydrogen from the catalyst to an generated imine is the hallmark of a transition metal mediated catalytic -alkylation of amines. However, such a borrowing hydrogen mechanism with a transition metal free catalytic system which stores hydrogen molecules in the catalyst backbone is yet to be established. Herein, we demonstrate that a phenalenyl ligand can imitate the role of transition metals in storing and transferring hydrogen molecules leading to borrowing hydrogen mediated alkylation of anilines by alcohols including a wide range of substrate scope.

Switching between mono and doubly reduced odd alternant hydrocarbon: designing a redox catalyst.

Since the early Hückel molecular orbital (HMO) calculations in 1950, it has been well known that the odd alternant hydrocarbon (OAH), the phenalenyl (PLY) system, can exist in three redox states: closed shell cation (12π e), mono-reduced open shell neutral radical (13π e) and doubly reduced closed shell anion (14π e). Switching from one redox state of PLY to another leads to a slight structural change owing to its low energy of disproportionation making the electron addition or removal process facile. To date, mono-reduced PLY based radicals have been extensively studied.

From CO activation to catalytic reduction: a metal-free approach.

Over exploitation of natural resources and human activities are relentlessly fueling the emission of CO in the atmosphere. Accordingly, continuous efforts are required to find solutions to address the issue of excessive CO emission and its potential effects on climate change. It is imperative that the world looks towards a portfolio of carbon mitigation solutions, rather than a single strategy.

Transition metal-free catalytic reduction of primary amides using an abnormal NHC based potassium complex: integrating nucleophilicity with Lewis acidic activation.

An abnormal N-heterocyclic carbene (aNHC) based potassium complex was used as a transition metal-free catalyst for reduction of primary amides to corresponding primary amines under ambient conditions. Only 2 mol% loading of the catalyst exhibits a broad substrate scope including aromatic, aliphatic and heterocyclic primary amides with excellent functional group tolerance. This method was applicable for reduction of chiral amides and utilized for the synthesis of pharmaceutically valuable precursors on a gram scale.