Preparation of Diynes via Selective Bisalkynylation of Zirconacycles
journal contributionposted on 2000-09-19, 00:00 authored by Yuanhong Liu, Chanjuan Xi, Ryuichiro Hara, Kiyohiko Nakajima, Akiko Yamazaki, Martin Kotora, Tamotsu Takahashi
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.