4
836
M. Shevlin / Tetrahedron Letters 51 (2010) 4833–4836
0
0
0
8
.
For a discussion of catalyst features necessary for Ar–Cl cross-coupling, see
Martin, R.; Buchwald, S. L. Acc. Chem. Res. 2008, 41, 1461–1473.
2 ,4 ,6 -triisopropylbiphenyl (95.3 mg, 200
l
mol). The vial was evacuated and
filled with N three times, purged with a gentle stream of N
2
2
for 10 min, H SO
2
4
9
.
For Pd-catalyzed cyanation of Ar–Cl, see (a) Schareina, T.; Jackstell, R.; Schulz,
T.; Zapf, A.; Cotté, A.; Gotta, M.; Beller, M. Adv. Synth. Catal. 2009, 351, 643–648;
(2.0 mL, 50 mM in DMA) was added, and the catalyst mixture was stirred in an
oil bath at 80 °C for 30 min to give a homogeneous coffee-brown solution. To a
100 mL two-neck round-bottomed flask were added Zn dust (13.1 mg,
(
b) Cheng, Y.; Duan, Z.; Li, T.; Wu, Y. Synlett 2007, 543–546; (c) Littke, A.;
Soumelliant, M.; Kaltenbach, R. F.; Cherney, R. J.; Tarby, C. M.; Kiau, S. Org. Lett.
007, 9, 1711–1714; (d) Schareina, T.; Zapf, A.; Magerlein, W.; Muller, N.;
200
(940 mg, 5.0 mmol). The flask was equipped with a magnetic stirbar, septum,
and gas inlet, evacuated and filled with N three times, and purged with N for
10 min. DMA (20 mL) and catalyst solution (1.0 mL, 50 mol Pd, 1% loading)
2
lmol, 10 micron), Zn(CN) (352.3 mg, 3.0 mmol), and 4-chlorobiphenyl
2
Beller, M. Tetrahedron Lett. 2007, 48, 1087–1090; (e) Chobanian, H. R.; Fors, B.
P.; Lin, L. S. Tetrahedron Lett. 2006, 47, 3303–3305; (f) Jin, F.; Confalone, P. N.
Tetrahedron Lett. 2000, 41, 3271–3273; For Ni-catalyzed cyanation of Ar–Cl, see
2
2
l
were added and the flask was stirred in an oil bath at 120 °C for 1 h.
Quantitative HPLC analysis using authentic 2-cyanobiphenyl purchased from
Acros indicates 100% assay yield. The reaction mixture was added to 200 mL
(
g) Cassar, L.; Ferrara, S.; Foá, M. Adv. Chem. Series 1974, 132, 252–273
(
Homogeneous Catal. 2, Symp., 1973).
1
1
1
1
0. Shelby, Q.; Kataoka, N.; Mann, G.; Hartwig, J. J. Am. Chem. Soc. 2000, 122,
0718–10719.
1. Walker, S. D.; Barder, T. E.; Martinelli, J. R.; Buchwald, S. L. Angew. Chem., Int. Ed.
004, 43, 1871–1876.
2. Huang, X.; Anderson, K. A.; Zim, D.; Jiang, L.; Klapars, A.; Buchwald, S. L. J. Am.
Chem. Soc. 2003, 125, 6653–6655.
H
2
O and 20 mL saturated NaCl was added. The aqueous layer was extracted
and concentrated.
1
with 3 ꢁ MTBE, combined organics were dried over MgSO
4
The residue was purified via silica gel chromatography (2–20% EtOAc in
2
hexane) to give a white solid (851 mg, 95%). Spectroscopic data match those
previously reported in the literature; GC/MS (EI) calcd for C13
found: 179.05.
+
H
9
N (M ): 179.07,
3. For Ph
reactions, see Denmark, S. E.; Smith, R. C.; Tymonko, S. A. Tetrahedron 2007,
3, 5730–5738.
4. We also found one report of (dppp)PdSO
3
PO-stabilized [(allyl)PdCl]
2
catalysts in arylsilanolate coupling
18. A little material was lost due to product volatility with unoptimized workup
conditions.
19. For stoichiometric cobalt-mediated cyanation of vinyl chlorides, see Stuhl, L. S.
J. Org. Chem. 1985, 50, 3934–3936.
6
1
4
used for CO–ethylene
copolymerization; see Cavinato, G.; Vavasori, A.; Toniolo, L.; Ronchin, L.;
Dall’Acqua, F.; Dolmella, A. Inorg. Chim. Acta 2005, 358, 4555–4562.
20. Investigation of the mechanistic effects of sulfuric acid on the catalyst system
has been hampered by the poor solubility of the ligand in polar aprotic solvents
and the heterogeneity of the reaction mixture. It does not appear that sulfuric
acid markedly changes the nature of the ligand–metal complex, as no change
in the 31P NMR signal is observed upon its addition. It also does not appear that
the ligand–metal complex is reduced to palladium(0) prior to introduction to
the reaction mixture, as no signal corresponding to the ligand oxide is observed
in the 31P NMR spectrum. By comparison, the ligand triphenylphosphine
1
5. For PdSO
M.; Gannett, P. G.; Shaughnessy, K. H. J. Org. Chem. 2003, 68, 6767–6774.
6. Yields ranged from 0% to 86% with different lots of PdSO O.
ꢀ2H
7. General procedure for cyanation of aryl chlorides: Anhydrous DMA was sparged
4
-catalyzed Suzuki coupling, see Western, E. C.; Daft, J. R.; Johnson, E.
1
1
4
2
with a gentle stream of N
2
for 30 min prior to use. A 50 mM solution of H
2
SO
4
was prepared with 10 mL DMA and 26.8
l
L concd H SO and sparged with N
2
4
2
for 10 min. To an 8 mL vial equipped with a magnetic stirbar and septum cap
were added Pd(OAc) (22.5 mg, 100 mol) and 2-dicyclohexylphosphino-
spontaneously reduces its Pd(OAc)
A.; M’Barki, M. A. Organometallics 1992, 11, 3009–3013.
2
complex to Pd(0). See Amatore, C.; Jutand,
2
l