Recent Advances in Ruthenium(II)-Catalyzed C−H Bond Activation and Alkyne Annulation Reactions

Synthesis of Multisubstituted 1-Naphthoic Acids via Ru-Catalyzed C-H Activation and Double-Alkyne Annulation under Air

An efficient [2 + 2 + 2] benzannulation of phthalic acids/anhydrides with two alkynes was developed for synthesis of multisubstituted 1-naphthoic acids via Ru-catalyzed C-H activation. The reaction preceded well using atmospheric oxygen as the sole oxidant with high atom/step economies. Facilitated by the free carboxyl group, the products can be easily converted to diverse polycyclic molecules.

Decarboxylative [4+2] annulation of arylglyoxylic acids with internal alkynes using the anodic ruthenium catalysis

A new electrochemical decarboxylative [4+2] annulation of arylglyoxylic acids with internal alkynes involving C-H functionalization by means of a cooperative anode and ruthenium catalysis is presented. This reaction represents a mechanistically novel strategy as an ideal supplement to the decarboxylative [4+2] annulation methodology by employing an electrooxidative process to avoid the use of an additional external oxidizing reagent and utilizing H₂O as the carboxyl oxygen atom source to be engaged in the synthesis of 1H-isochromen-1-ones.

Transition metal catalysed direct selanylation of arenes and heteroarenes

Transition metal catalysed C-H functionalization has reached an exciting level of sophistication, and, today, it represents a paradigm shift from the standard logic of synthetic chemistry. The direct conversion of C-H bonds into C-heteroatoms remains, however, a critical challenge. Nowadays, there is a great demand in general synthetic chemistry in, for example, the materials science for the development of straightforward C-Se bond formation, in order to fulfil the practical requirements. In this sense, this review summarizes recent outstanding advances in the C-Se bond formation through transition metal-catalysed direct selanylation, providing new insights into their mechanistic aspects and disclosing effective synthetic routes with high atom economy. In addition, this review intends to show the growing opportunities to construct complex chemical scaffolds containing selenium atoms.

Cascade intramolecular imidoylation and C–H activation/annulation of benzimidoyl chlorides with alkynes: one-pot synthesis of 7H-dibenzo[de,h]quinoline analogues

Described herein is a cascade Lewis acid-promoted intramolecular Friedel–Crafts-type imidoylation and Rh(iii)-catalyzed C–H activation/annulation of benzimidoyl chlorides and alkynes, providing a divergent synthetic shortcut to 7H-dibenzo[de,h]quinoline analogues.

C–H and N–H bond annulation of aryl amides with unactivated olefins by merging cobalt(iii) and photoredox catalysis

A mild, environment-friendly protocol has been developed to carry out the [4+2] annulation of aryl amides with unactivated olefins.

A ruthenium-catalyzed free amine directed (5+1) annulation of anilines with olefins: diverse synthesis of phenanthridine derivatives

A ruthenium(ii)-catalyzed cross-ring (5+1) annulation between 2-aminobiphenyls and activated olefins is disclosed for succinct synthesis of valuable phenanthridine scaffolds.