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Updated: Jul 6, 2025

Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts
Published on: February 24, 2015
Enantioselective Alkynylation of Unstabilized Cyclic Iminium Ions
Weiye Guan1, Samantha O Santana1, Jennie Liao1
1Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, United States.
Abstract:
An enantioselective copper-catalyzed alkynylation of unstabilized cyclic iminium ions has been developed. Whereas such alkynylations typically utilize pyridinium, quinolinium and isoquinolinium intermediates, this method enables use of cyclic iminium ions unstabilized by resonance. With the use of a Lewis acid and copper catalyst, these iminium ions are generated in situ from readily available hemiaminal methyl ethers and transformed into highly enantioenriched α-alkynylated cyclic amines. A variety of terminal alkynes can be incorporated in high yields and enantiomeric excesses.
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