Facile Construction of Furanoacenes by a Three-Step Sequence Going through Disilyl-exo-cyclic Dienes

Visible-Light-Induced Palladium-Catalyzed Construction of Polyarylfuran Skeletons via Cascade Aryl Radical Cyclization and C(sp3)-P(V) Bond Cleavage

Herein, a novel and expedient method was established for the synthesis of polyarylfuran derivatives. The coupling of allenylphosphine oxide and bromophenol or bromonaphthol enabled by visible light and palladium catalysis directly furnishes polyarylfuran skeletons, which involves a radical tandem cyclization and cascade C(sp³)-P(V) bond cleavage. This protocol features easy operation, a broad substrate scope, and a high step economy, affording polyarylfurans in moderate to good yields.

Advances in the synthesis of nitrogen-containing heterocyclic compounds by in situ benzyne cycloaddition

Nitrogen-containing heterocyclic compounds are prevalent in various natural products, medicines, agrochemicals, and organic functional materials. Among strategies to prepare nitrogen-containing heterocyclic compounds, pathways involving benzyne intermediates are attractive given that they can readily assemble highly diverse heterocyclic compounds in a step-economical manner under transition-metal-free conditions. The synthesis of nitrogen-containing heterocyclic compounds from benzyne intermediates offers an alternative strategy to the conventional metal-catalyzed activation approaches. In the past years, chemists have witnessed the revival of benzyne chemistry, mainly attributed to the wide application of various novel benzyne precursors. The cycloaddition of benzynes is a powerful tool for the synthesis of nitrogen-containing heterocyclic compounds, which can be constructed by [n + 2] cyclization of benzyne intermediates in situ generated from benzyne precursors under mild reaction conditions. This review focuses on the application of cycloaddition reactions involving in situ benzynes in the construction of various nitrogen-containing heterocyclic compounds.