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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R 1<br />
R 1<br />
4. Sonogashira Reaction:<br />
H + R 2<br />
5. Tsuji-Trost Reaction:<br />
X<br />
+<br />
6. Negishi Reaction:<br />
ZnR<br />
X<br />
R 1 = alkyl, aryl, v<strong>in</strong>yl<br />
R 2 = aryl, benzyl, v<strong>in</strong>yl<br />
X= Br, Cl, I, OTf<br />
NuH<br />
cat. [Pd 0 L n] R 2<br />
cat. CuX, base<br />
cat. [Pd 0 L n]<br />
base<br />
X= Br, Cl, OCOR, OCO 2R, OSO 2R, P(=O)(OR) 2<br />
NuH= ß-dicarbonyls, ß-ketosulfones, enam<strong>in</strong>es, enolates<br />
2 R3<br />
+<br />
X<br />
R 1<br />
cat. [Pd 0 L n] R 1<br />
R 1 = alkyl, alkynyl, aryl, v<strong>in</strong>yl<br />
R 3 = acyl, aryl, benzyl, v<strong>in</strong>yl<br />
X= Br, I, OTf, OTs<br />
Figure 2.2. Palladium-catalyzed <strong>cross</strong>-coupl<strong>in</strong>g <strong>reaction</strong>s<br />
(Source: Nicolaou et al. 2005)<br />
Among these <strong>reaction</strong>s catalyzed by <strong>palladium</strong>, four ma<strong>in</strong> catalytic methods are<br />
used for the synthesis of biaryls which are important build<strong>in</strong>g blocks of numerous<br />
agrochemicals, pharmaceuticals, natural products, polymers, advanced materials, liquid<br />
crystals, and ligands. These are Kharasch Reaction, Negishi Reaction, Stille Reaction<br />
and Suzuki Reaction. Compared to other methods of biaryl synthesis, Suzuki <strong>cross</strong>coupl<strong>in</strong>g<br />
<strong>reaction</strong> is the most important one for <strong>in</strong>dustrial and academic area.<br />
Nu<br />
R 3<br />
7