Page 753 - Advanced Organic Chemistry Part B - Reactions & Synthesis

Carbenoid imidazolidene ligands such as C can also be used in conjunction with 729
Pd dba , and this method has been applied to -arylpropanoic acids (NSAIDS) such
2
as naproxen. 175 SECTION 8.2
Reactions Involving
Organopalladium
Intermediates
CH 3
Br O –
CH 3 1% Pd(dba) CO C H
+ OC H 2 2 5
O 2 5 1% ligand C
CH 3 CH O
3
LiN (C H )
6 11 2
N + N

cat C

Highly arylated ketones have been prepared successfully. For example, arylation
of the enolate of the deoxybenzoin 4 gives 1,1,2-triarylethanones that are related to
substances such as tamoxifen. 176

OCH 3 OCH 3
OCH 3 OCH 3
2 mol % Pd(OAc) 2
5 mol % PPh
+ PhBr 3
2
3
O K CO , xylene O
150°C
OCH 3 OCH 3 83%
4 OCH 3 OCH 3

Similar reactions have been carried out using polymer-supported catalysts. 177
Arylations have also been extended to zinc enolates of esters (Reformatsky
reagents). 178

CH CHCO C(CH ) + Br CO C H [(t -Bu) PPdBr] 2 CH CH CO C H
3 3
2
3
3
2 2 5
2 2 5
3
ZnBr C H O C 81%
2 5
2
These conditions can also be applied to enolates prepared from -halo amides.
175
M. Jorgensen, S. Lee, X. Liu, J. P. Wolkowski, and J. F. Hartwig, J. Am. Chem. Soc., 124, 12557 (2002).
176
F. Churruca, R. SanMartin, I. Tellitu, and E. Dominguez, Org. Lett., 4, 1591 (2002).
177 F. Churruca, R. SanMartin, M. Carrill, I. Tellitu, and E. Dominguez, Tetrahedron, 60, 2393 (2004).
178
T. Hama, X. Liu, D. A. Culkin, and J. F. Hartwig, J. Am. Chem. Soc., 125, 11176 (2003).