Handbook of Functionalized Organometallics Applications in S

12.2 Functionalized Organozirconocene Derivatives
The extreme mildness and rapidity with which vinyl zirconocenes undergo
transmetallation reactions with cyanocuprate at low temperatures leads directly to
the corresponding functionalized mixed cuprate with internal electrophiles. Introduction
of an a,b-unsaturated ketone affords the expected 1,4-adduct in good isolated
yield. This simple, one-pot process has been applied to alkynes, which possess
a nitrile 2, ester 3 or chloride 4 residues (Scheme 12.4) [5].
H
H
H
H
H
2
3a
1. Me 2CuCNLi 2
THF, -78 ºC
2.
O
3a
CN
O
1. Me 2CuCNLi 2
THF, -78 ºC
2.
O
3b
O
1. Me 2CuCNLi 2
THF, -78 ºC
2.
O
4
Scheme 12.4
O Ph
Cl
O
Cp 2Zr(H)Cl
THF, r.t.
OSi(Pr-i) 3
O
OSi(Pr-i) 3
O
O
Cp 2Zr(H)Cl
THF, r.t.
ClCp 2Zr
Cp 2Zr(H)Cl
THF, r.t.
Cp 2Zr(H)Cl
THF, r.t.
Cp 2Zr(H)Cl
THF, r.t.
71%
ClCp 2Zr
78 %
78 %
ClCp 2Zr
ClCp 2Zr
O
ClCp 2Zr
O
O Ph
O
OSi(Pr-i) 3
OSi(Pr-i) 3
Cl
CN
1. Me 2CuCNLi 2
THF, -78 ºC
2.
O Ph
O
O
O
O
1. Me 2CuCNLi 2
THF, -78 ºC
2.
O
OSi(Pr-i) 3
OSi(Pr-i) 3
O
O
95%
75 %
Cl
505
CN