Recent Advances in the Synthesis of Isocoumarins and Polyaromatic Hydrocarbons for Photoactive Materials

The discovery of transition metal-catalyzed selective activation of aromatic carbon–hydrogen bonds in 1993 has opened a new era in the synthesis of carbo- and heterocyclic compounds. This review covers the applications of oxidative annulations of aromatic compounds with alkynes involving CH activation for the synthesis of isocoumarins and polyaromatic hydrocarbons (PAHs). The limitations, advantages, and mechanical aspects of this approach as well as the current tendencies in the application of the reaction products for photoactive materials are discussed.

CH Activation by a Heavy Metal Cation: Production of H2 from the Reaction of Acetylene with C4H4-Os(+) in Gas phase

While first-row transition metal cations, notably Fe(+), catalyze the gas-phase conversion of acetylene to benzene, a distinct path is chosen in systems with Os, Ir, and Rh cations. Rather than losing the metal cation M(+) from the benzene–M(+) complex, as is observed for the Fe(+) system, the heavy metal ions activate CH bonds. The landmark system C4H4-Os(+) reacts with acetylene to produce C6H4-Os(+) and dihydrogen. Following our work on isomers of the form C2nH2n-Fe(+), we show by DFT modeling that the CH bonds of the metalla-7-cycle structure, C6H6-Os(+), are activated and define the gas-phase reaction path by which H2 is produced. The landmark structures on the network of reaction paths can be used as a basis for the discussion of reactions in which a single Os atom on an inert surface can assist reactions of hydrocarbons.

CH-Activation reactions of nitroarenes: current status and outlook

Ring substitution reactions of nitroarenes remain an under-developed area of organic synthesis, confined to narrow domains of SNAr and SNArH reactions. Searching for alternate methodologies, we took stock of CH-activation...

Linear free energy relationships for transition metal chemistry: case study of CH activation with copper–oxygen complexes

We propose a computational framework for developing Taft-like linear free energy relationships to characterize steric effects on the catalytic activity of transition metal complexes.

3-Thienyl/benzothienylchromones. Synthesis and properties

This mini-review for the first time summarizes and systematizes all the data available in the literature on the synthesis and properties of 3-thienyl/benzothienylchromones, starting from 1960. Two main approaches to the formation of target structures are presented. The conditions of cyclization reactions, oxidative rearrangement, transition metals catalyzed CH activation and annulation reactions, etc. are discussed. Testing data for some types of biological activity of a number of the 3-thienyl/benzothienylchromones and the products of their transformation into the pyrazole cycle are given.