Page 749 - Advanced Organic Chemistry Part B - Reactions & Synthesis

OMe 725
Ph Br Pd(PPh ) Ph SECTION 8.2
3 4
+ MeO ZnCl
C H Ph C H Ph Ref. 160 Reactions Involving
2 5
2 5
Organopalladium
Intermediates
Scheme 8.10 shows some representative coupling reactions with organomag-
nesium and organozinc reagents. Entry 1 shows a biaryl coupling accomplished using
an arylzinc reagent. Entry 2 involves the use of a chelating ligand with an aryl triflate.
The bis-phosphines dppe, dppp, and dppb were also effective for this coupling. Entry 3
is an example of use of a vinyl triflate. Entries 4 and 5 illustrate the use of perfluorobu-
tanesulfonate (nonaflate) as an alternative leaving group to triflate. The organozinc

Scheme 8.10. Palladium-Catalyzed Cross Coupling of Organometallic Reagents with
Halides and Sulfonates

a
1 CH 3 CH
Pd(PPh ) , 3
3 4
ZnCl + Br NO 1 mol % NO
2 2
78%
2 b
PdCl
+ PhMgBr 2
CH 3
O SCF (CH ) N PPh 95%
3 3 3 2 2
3 c
CH CH CH CH
3 3 3 3
CH 3 Pd(PPh ) CH 3
3 4
O SCF + PhZnCl 2 mol % Ph
3 3
55% Cl
CF O SC F
4 9
3
4 d 3 CF 3
+ BrZn Cl Pd(dba) , 2 mol %
2
dppf, 2 mol %
96%
(dba = dibenzylideneacetone)
5 e F
OSO C F Pd(dba)
2
4 9
+ ClZn F 2
dppf, 2 mol %
CO C H
5
2
2
CO C H 5
2
2
91%
6 f
CH CH
CH 3 3
1) IpcBH 3
2
2) (C H ) BH H ICH CH(CH ) CH 3 H
2 3
2 5 2 CH ) CH
)
ZnCH(CH 3 2 Pd(dba) , 2 mol % CH(CH 2 3 3
3) (i - Pr) Zn 2
2
(o - ol) P, 4 mol % 35%
3
7 g Pd(dppb)Cl , CH 3 CH 3
CH 3 CH 3 14 mol % 2 Ph CO C H 5
2
2
PhZnCl + Cl CO C H 5
2
2
Cl 86%
Cl
a. E. Negishi, T. Takahashi, and A. O. King, Org. Synth., VIII, 430 (1993).
b. T. Kamikawa and T. Hayashi, Synlett, 163 (1997).
c. G. Stork and R. C. A. Issacs, J. Am. Chem. Soc., 112, 7399 (1990).
d. M. Rottlander and P. Knochel, J. Org. Chem., 63, 203 (1998).
e. F. Bellina, D. Ciucci, R. Rossi, and P. Vergamini, Tetrahedron, 55, 2103 (1999).
f. A. Boudier and P. Knochel, Tetrahedron Lett., 40, 687 (1999).
g. A. Minato, J. Org. Chem., 56, 4052 (1991).
160
R. B. Miller and M. I. Al-Hassan, J. Org. Chem., 50, 2121 (1985).