Nucleophilic displacement with transition metal catalysis

7 Nucleophilic displacement with transition metal catalysis 

---

Finding ways to make nonactivated haloarenes susceptible to nucleophilic attack has always been a great challenge for chemists. Catalysis with transition metal complexes has proven to be efficient in activating inert aryl-halogen bonds and performing various nucleophilic displacement reactions (Eq. 25) [ 178]. The... 

Even where a nucleophilic displacement of halide is feasible, the use of transition-metal catalysis, such as with copper (for iodides) or palladium, generally offers much milder conditions (4.2.10). ... 

Figure 27-13 Proposed mechanism and transition state structure for the synthetic nucleotidyltransfer activity of DNA polymerase 3 (and other DNA polymerases). The chain-terminating inhibitor dideoxy CTP is reacting with the 3 -OH group of a growing polynucleotide primer chain. This -OH group (as -0 ) makes an in-line nucleophilic attack on Pa of the dideoxy-CTP. Notice the two metal ions, which interact with the phospho groups and which are held by three aspartate side chains. Two of the latter, Asp 190 and Asp 256, are present in similar positions in all of the polymerases. The active centers for the hydrolytic 3 -5 and 5 -3 exonuclease activities of some of the polymerases also appear to involve two-metal catalysis and in-line displacement. See Sawaya et al.27i...

Catalyzed displacements. The very important use of transition metals to catalyze displacements of halides is covered in Section 3.2.3.11.2 displacements with nucleophiles which were previously difficult or impossible can now be achieved with ease using such catalysis. 

---