chapter 2 palladium catalysts in suzuki cross- coupling reaction
chapter 2 palladium catalysts in suzuki cross- coupling reaction
chapter 2 palladium catalysts in suzuki cross- coupling reaction
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Table 5.7. The Optimization of Pd-NaY catalyzed Suzuki <strong>reaction</strong> of 4-bromoanisole<br />
H 3CO<br />
over the Pd concentration of 0.005% a<br />
4-Bromoanisole<br />
+<br />
Br<br />
Phenylboronic acid<br />
%0.005 mmol [Pd(NH3) 4] +2 B(OH) 2<br />
-Y<br />
Base, Solvent, 100°C<br />
H 3CO<br />
4-methoxybiphenyl<br />
Entry Base Solvent (Solvent/H2O) Conversion% b Yield% b<br />
1 c,d Na2CO3 DMF(1/1) 75 71<br />
2 c Na2CO3 DMF(1/1) 87 86<br />
3 Cs2CO3 DMF(1/1) 52 52<br />
4 K2CO3 DMF(1/1) 62 62<br />
5 Na2CO3 NMP(1/1) 81 81<br />
6 Na2CO3 DMA(1/1) 96 89<br />
7 Na2CO3 DMA(1/2) 82 82<br />
8 Na2CO3 DMA(1/3) 74 74<br />
9 Na2CO3 DMA(2/1) 63 63<br />
10 e Na2CO3 DMA(1/1) 94 94<br />
11 e,f Na2CO3 DMA(1/1) 93 94 (92) g<br />
12 f Na2CO3 DMA(1/1) 95 87<br />
13 h Na2CO3 DMA(1/1) 96 91<br />
a Typical <strong>reaction</strong> conditions: 10 mmol of 4-bromoanisole, 12 mmol of PhB(OH)2 (Fluka),<br />
0.005% Pd, 20mmol Na2CO3 , 20ml Solvent/H2O, under <strong>in</strong>ert atmosphere at 100 °C, 30m<strong>in</strong>. b<br />
GC yield based on 4-bromoanisole. c 5 mmol 4-bromoanisole, 6mmol PhB(OH)2, 10mmol<br />
Na2CO3, 10ml DMF/water(1/1) was used. d PhB(OH)2 was supplied from Aldrich. e In the<br />
presence of zeolite (1g). f Open to the atmosphere. g Isolated yield. h PhB(OH)2 was supplied<br />
from Merck.<br />
We also tried to lower Pd concentration to 0.001% and performed <strong>reaction</strong> us<strong>in</strong>g<br />
the Merck reagent of phenylboronic acid under optimized conditions. However, the<br />
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