ABSTRACT
The use of palladium catalysts in fused ring synthesis has been increasingly noteworthy in recent years in organic synthesis. It has a lot of potential compared to other transition metal catalysts, because of its one-of-a-kind feature that makes them more widely applicable in a variety of disciplines application. Palladium is important in a variety of Heck processes, including intramolecular, intermolecular, and reductive Heck reactions, which produce diverse carbocycles and heterocycles of biological importance. Under optimal reaction conditions, carbocyclization or heterocyclization occurs, resulting in the production of numerous structural building blocks of naturally occurring compounds. Beside intramolecular Heck-type reactions, cycloaddition, cycloalkylation, oxidative coupling, C-H functionalization, cross-coupling reactions, and carboamidation reactions have also been employed extensively to access fused carbo- and heterocycles of immense biological importance. This review article provides a well-summarized discussion (since 2001) on fused carbo- and heterocycle ring synthesis using palladium catalysts, overviewing their applications, and mechanistic insights.
Subject(s)
Palladium , Transition Elements , Palladium/chemistry , Charcoal , Catalysis , Cycloaddition ReactionABSTRACT
The hydroarylation of alkynes, alkenes, and allenes is a cost-effective and efficient way to incorporate unsaturated moieties into aromatic substrates. This review focuses on gold-catalyzed hydroarylation, which produces aromatic alkenes, diaryl-alkanes, heterocycles, carbocycles, and arylbutadienes by directly functionalizing C-H bonds. Without the need for prefunctionalization, direct functionalization of aromatic C-H bonds with unsaturated moieties (alkyne, alkene, allene) provides an efficient synthetic strategy with fewer reaction steps. This review offers an overview of the recently developed hydroarylation processes catalyzed by gold. Mechanisms of hydroarylation via alkyne, alkene, allene, and arene activation receive special attention.
