Highly substituted enyne formation by coupling reaction of alkenylzirconium compounds with alkynyl halides
摘要:
Alkenylzirconium compounds, which were prepared by carbozirconation or hydrozirconation of alkynes, reacted with alkynyl halides in the presence of CuCl to give highly substituted 1,3-enynes in good yields. This reaction was done conveniently in one-pot from alkynes. (C) 1997 Elsevier Science Ltd.
Reaction of alkynyl halides with in situ prepared zirconacyclopentanes, -pentenes, and -pentadienes in the presence of CuCl under mild reaction conditions afforded alkynes or diynes. Control of the reaction conditions selectively afforded monoalkynylation products of zirconacycles. Reaction of zirconacycles with 2 equiv of alkynyl halides resulted in the formation of diynes. Selective monoalkynylation of zirconacycle with an alkynyl halide, followed by reaction with a different alkynyl halide, afforded unsymmetrical diynes. Bisalkynylation product of zirconacyclopentadiene was gradually converted into a tricyclic compound.