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Updated: Aug 9, 2025

Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts
Published on: February 24, 2015
Base-Promoted Decarboxylative Annulation of Methyl 2-(2-Bromophenyl)acetates and Ynones to Access Benzoxepines
Lu-Lu Chen1, Feng Li1, Qing Yang1
1Henan Engineering Research Center of Functional Materials and Catalytic Reaction, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China.
Abstract:
A simple and efficient base-mediated decarboxylative annulation of ynones with methyl 2-(2-bromophenyl)acetates has been developed. A broad range of benzoxepines were prepared with a broad substrate scope and high regioselectivity in moderate to excellent yields under transition-metal-free conditions. This method proceeds through a tandem [2 + 4] annulation, ring-opening decarboxylative reaction, and the intramolecular nucleophilic aromatic substitution reaction. Additionally, the key intermediates were successfully obtained and characterized unambiguously by single-crystal X-ray crystallography, which could favorably support a decarboxylative annulation mechanism. Furthermore, gram-scale reaction and synthetic applications for the further functionalization are also studied.
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