Alkenylzirconocene-Mediated Preparation of Alkenylphosphines

Alkenylphosphines with various substituents were prepared by the reaction of an alkenylzirconocene
with a chlorophosphine. Reactions of (α-unsubstituted alkenyl)zirconocenes with Ph2PCl or PhPCl2 gave
the corresponding alkenylphosphines in good yields. On the other hand, direct reactions of (α-unsubstituted
alkenyl)zirconocenes with iPr2PCl did not proceed. Analogously, (α-substituted alkenyl)zirconocenes did
not react with chlorophosphines directly. However, these reactions proceeded in the presence of CuCl
affording the corresponding alkenylphosphines as CuCl complexes. Treatment of the copper complexes
with Na2(dtc) (dtc = N,N-diethyldithiocarbamate) or Na4(edta) liberated free alkenylphosphines from
the copper centers. The overall protocol could be applicable to preparation of a variety of alkenylphosphines
from alkynes via alkenylzirconocene species.