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3-Hexyne, aka diethylacetylene, is a symmetric alkyne that is used in organic and organometallic synthesis. It first appeared in British patent 279,095 (1926) to Michael George Corson, who heated ethanol and calcium carbide under pressure to produce 3-hexyne. Corson made additional alkynes in this way, starting with alkyl and aryl alcohols and chlorides.

In 1937, Edward A. Bried and G. F. Hennion at the University of Notre Dame (South Bend, IN) reported a different method for . In a three-reaction sequence in liquid ammonia, an alkyl halide or sulfate reacts with sodium acetylide to form a terminal alkyne; the alkyne reacts with sodamide to form its acetylide; and that product reacts with the same or another halide or sulfate to generate the final product. All three reactions take place simultaneously in liquid ammonia solvent.

An example of 3-hexyne in organometallic synthesis was reported in 1984 by R. B. Maynard, L. Borodinsky, and R. N. Grimes at the University of Virginia (Charlottesville) and N. Hosmane at Virginia Polytechnic Institute (Blacksburg). In , the authors showed that 3-hexyne reacts with pentaborane(9)¹ in triethylamine solvent ².

This January, Dibyendu Mallick at Presidency University and Biplab Maji and co-workers at the Indian Institute of Science Education and Research (both in Kolkata) provided an example of using 3-hexyne in organic synthesis. In a wide-ranging article, they described a cobalt-catalyzed enantioselective reductive coupling of imines with internal alkynes, including 3-hexyne. The imines and alkynes reacted over a cobalt complex catalyst with elemental zinc as the reductant and tetrahydrofuran as the solvent to in up to 89% yield and almost 100% enantiomeric excess.

1. CAS Reg. No. 19624-22-7.
2. CAS Reg. No. 80583-48-8.