Triethylborane-Induced Radical Reaction of Alkynylgallium with α-Halo Carbonyl Compounds

Treatment of terminal acetylenes with butyllithium, followed by an addition of gallium trichloride, afforded the corresponding alkynylgallium reagents. The reaction of the resulting alkynylgallium with α-halo carbonyl compounds in the presence of triethylborane as a radical initiator provided β,γ-acetylenic carbonyl compounds in good yields.