Global warming concern has dramatically increased interest in using CO2 as a feedstock for preparation of value-added compounds, thereby helping to reduce its atmospheric concentration. Here, we describe a dinuclear copper(I) complex that is oxidized in air by CO2 rather than O2; the product is a tetranuclear copper(II) complex containing two bridging CO2-derived oxalate groups. Treatment of the copper(II) oxalate complex in acetonitrile with a soluble lithium salt results in quantitative precipitation of lithium oxalate. The copper(II) complex can then be nearly quantitatively electrochemically reduced at a relatively accessible potential, regenerating the initial dinuclear copper(I) compound. Preliminary results demonstrate six turnovers (producing 12 equivalents of oxalate) during 7 hours of catalysis at an applied potential of -0.03 volts versus the normal hydrogen electrode.

Selective radical generation in conjugated oligomeric o-aryleneethynylenes initiates an intramolecular cascade which involves five fast radical cyclizations followed by aromatization via a 1,5-H shift with a >93% yield per step. This radical cascade transformation opens a new avenue for the systematic and controlled preparation of functionalized graphene nanoribbons where, potentially, each of the peripheral aromatic rings can be different.

The Sonogashira/5-endo-dig/6-endo-dig cascade fuses a polycyclic aromatic backbone to the electron-rich furan subunit. The transformation proceeds in modest yields as a one-pot reaction. Efficiency of the full cascade is increased by removal of base prior to the addition of gold catalyst. Under these conditions, conversion to the full cascade products is achieved in nearly quantitative yields without purification of the intermediate products. Extension of the cascade toward triynes opens access to benzofuran-fused chrysene derivatives.

No abstract

A new type of concerted cycloaddition-fragmentation reaction utilizing carbamic acid as the amine source is herein reported. This method will require the use of carbamic acid for these reactions that are driven forward by elimination of a highly stable small molecule (CO 2 ). The formation of this gaseous byproducts would make this type of concerted reaction irreversible, driving the reaction to completion. A theoretical study was completed at the B3LYP/6-31G(d,p) level, providing evidence of the feasibility of this reaction. Additional computation work was done to show how adding electron donating groups to carbamic acid and electron withdrawing groups, such as fluorine, to the alkyne can additionally lower the activation energy of this reaction. This potential new methodology of unsaturated systems would allow for hydroaminations without the need for transition metal catalysts.

The process affords the desired amines, required as non‐nucleophilic proton scavengers, exclusively from nitriles (I) in THF, hexanes or pentane.

Cross‐coupling of enediynes and iodophenol and subsequent cyclization result in the formation of a wide range of polyaromatic compounds.