Amido-amidate nickelacycles

Zero-valent metal complexes cannot be used directly for the synthesis of polypeptide hybrid block copolymers. However, N° -allyloxycarbonyl-amino acid allyl amides can be used as universal precursors for the amido-amidate nickelacycle initiators (Scheme 15.8). As shown in Scheme 15.8, the N°"-allyloxycarbonyl-amino acid derivatives may undergo tandem oxidative additions to nickel(O) giving the nickelacycle initiators. This method was initially employed for the synthesis of block copolypeptides and was then expanded by Deming and coworkers to a variety of hybrid structures. 

Fig. 7 Formation of amido-amidate nickelacycle form allyloxycarbonylaminoamides [69] X is a functional group, a polymer chain or another peptide...

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