Preparation of diynes via selective bisalkynylation of zirconacycles
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.
Liu
Y
Catalysis Research Center and Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-ku, Sapporo 060-0811, Japan, CREST, Science and Technology Corporation (JST), Sapporo 060-0811, Japan, and Department of Chemistry, Aichi Univ.
Xi
C
Hara
R
Nakajima
K
Yamazaki
A
Kotora
M
Takahashi
T