The Unprecedented Cobalt-Catalysed Oxidative Glaser Coupling under Reductive Conditions

Abstract

The cobalt-catalysed Glaser-type coupling of terminal alkynes was achieved utilising nitrobenzene as a stoichiometric oxidising agent under reductive conditions. The proposed electron transfer from zinc powder to a nitrobenzene coordinated to the cobalt centre initiates the coupling of the coordinated alkynes. Other aryl-, alkenyl-, alkyl-, and silylacetylenes besides phenylacetylene could also be coupled to generate the 1,3-diynes in moderate to very good yields.

Key words

alkyne - cobalt - Glaser coupling - oxidation - diynes

References

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4

The use of deuterated nitrobenzene led to the corresponding aniline and diazobenzene side products without loss of any deuterium labeling.