Air Tolerant Cadiot-Chodkiewicz and Sonogashira Cross-Couplings

Alfred K.K. Fung, Madison J. Sowden, Michelle L. Coote, Michael S. Sherburn

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Cadiot-Chodkiewicz cross-couplings generate an unsymmetric buta-1,3-diyne by way of a Cu(I)-catalyzed coupling between a terminal alkyne and a 1-haloalkyne. Despite their widespread use, Cadiot-Chodkiewicz reactions are plagued by the generation of symmetric buta-1,3-diyne side products, formed through competing: (a) formal reductive homo-coupling of the 1-haloalkyne and (b) oxidative (Glaser-Hay/Eglinton) homo-coupling of the terminal alkyne. To overcome this issue, a large excess of one of the two reacting alkynes is commonly deployed, and difficult separations of cross- and homo-coupled products are often encountered. Here, we demonstrate that the use of ascorbate as a reductant leads to a suppression of these unwanted side reactions, hence permitting excellent yields with a roughly stoichiometric ratio of reactants. The procedure also avoids an inert gas atmosphere and uses a sustainable solvent. A similar approach is effective for cross-couplings involving a Pd(0)/Pd(II) catalytic cycle, with air tolerant Sonogashira couplings also established.

Original languageEnglish
Pages (from-to)8145-8149
Number of pages5
JournalOrganic letters
Volume25
Issue number45
Early online date8 Nov 2023
DOIs
Publication statusPublished - 17 Nov 2023

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