Modern metal-catalyzed and organocatalytic methods for synthesis of coumarin derivatives: a review.

Coumarin is an important pharmaceutical structural motif, abundantly found in numerous commonly used drugs. Compounds containing this core show a broad spectrum of medicinal properties and biological activities. The increasing importance and wide usages of coumarin derivatives have drawn attention to its synthetic methods, among which metal-catalyzed and organocatalytic methods have proved the most effective. Several metal-catalyzed and/or organocatalytic synthetic strategies for coumarin have been investigated and reported in recent decades. This review focuses on more recent reports on catalysis methods for synthesizing coumarin and coumarin-like structures (including light-mediated methods and nano-catalysts), exploring the mechanistic aspects, simplicity, efficiency, repeatability, and other advantages and disadvantages of these methods.

A ruthenium-catalyzed alkenylation-annulation approach for the synthesis of indazole derivatives via C-H bond activation.

Ruthenium catalyzed oxidative alkenylation of N-aryl pyridazinediones and N-aryl phthalazinediones with acrylates and subsequent intramolecular cyclization of the resulting product in water as a green solvent were accomplished. Diverse derivatives of pyridazino[1,2-a]indazoles and indazolo[1,2-b]phthalazines were readily prepared in moderate to high yields by this methodology from easily accessible starting materials via cascade directed C-H bond activation/annulation reactions.