Palladium-Catalyzed Tandem Carbene Migratory Insertion and Intramolecular Cyclization: Synthesis of Chromeno[4,3-b]chromene Compounds
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Updated: Apr 14, 2026

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions
Published on: July 30, 2017
Xue Song Shang1, Nian Tai Li1, Hai Xiao Siyang1
1Shanghai Key Laboratory of Functional Materials Chemistry, Key Lab for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Meilong Road 130, Shanghai, China 200237.
Abstract:
Chromeno[4,3-b]chromene is a ubiquitous structural motif found in various pharmaceuticals and biologically active compounds. A concise palladium-catalyzed reaction of vinyl iodides and salicyl N-tosylhydrazones has been achieved to afford a series of compounds containing the chromeno[4,3-b]chromene scaffold in moderate to high yield. This tandem reaction involves palladium(II) carbene migratory insertion and intramolecular cyclization assisted by an O nucleophile and tolerates various functional groups.
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