C-C and C-S bonds are valuable in organic transformation for synthesizing various bioactive heterocycles. Increasing awareness of the step and atom economy for the reaction, organic chemists have promulgated the...

The quinazolinone template offers an exciting potential for transforming molecules into useful bioactivity. Herein, we report the first regioselective C–5 alkenylation of quinazolinone-coumarin conjugates via ruthenium­(II) catalyst using amide as a weak directing group. This methodology permits excellent regioselectivity, extensive substrate tolerance, and mild reaction conditions. In addition, it generates interesting fluorophores that show positive solvatochromism in the range from 404 nm (toluene) to 541 nm (methanol).

Palladium‐catalyzed [4+2] oxidative annulation of coumarin‐benzimidazoles with olefins for the synthesis of polycyclic aromatic hydrocarbons have been achieved. This synthetic protocol gives access to a wide range of structurally distinct imidazo[1,2‐a]chromeno[3,4‐c]pyridines in moderate to good yield with wide functional group tolerance. Further, photophysical properties of annulated scaffolds have been examined, which discloses their interesting solvatochromic emission behaviors.

Herein, one-pot cascade synthesis of chromeno[4,3-c]pyrazol-4-ones and their Ru(II)-catalyzed regioselective ortho-alkenylation using imine as a weak directing group are done with moderate to good yields. The reaction proceeds through a three-step domino process during which intermediates are also isolated in excellent yields. In addition, this methodology generates a number of interesting fluorophores with donor and acceptor groups, which show positive solvatochromism.