Palladium-Catalyzed Carbon-Nitrogen Bond Formation

Palladium-Catalyzed Carbon-Nitrogen Bond Formation 

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Palladium-catalyzed carbon-nitrogen bond formation (for reviews see [86— 91]) has been considerably developed in the past decade and, due to the omnipresence of nitrogen-containing compounds in natural products such as alkaloids or non-natural functional targets such as electron-rich zr-systems,... 

Palladium-Catalyzed Carbon-Nitrogen Bond Formation... 

As an alternative to primary amines in these double carbon-nitrogen bond forming reactions, Maes has demonstrated that 22 can undergo consecutive palladium-catalyzed carbon-nitrogen bond formation with orfho-dihalopyridine derivatives (Scheme 6.42). This reaction proceeds in good yield with a number of amidine variants, and provides a route to the construction of polycyclic imidazoles [54]. 

The exchange of a halogen to a classical nitrogen or oxygen nucleophile usually proceeds readily on the purine skeleton, without the necessity of using a transition metal catalyst. There are certain cases, however, where the palladium catalyzed carbon-heteroatom bond formation might take preference over noncatalysed methods. Inosine derivatives, for example,... 

Jiang L, Buchwald SL (2004) Palladium-catalyzed aromatic carbon-nitrogen bond formation. In de Meijere A, Diedeiich F (eds) Metal-catalyzed cross-coupling reactions, 2nd edn. Wiley-VCH, Weinheim... 

In certain cases, when the palladium or nickel catalyzed coupling is not efficient or fails completely, an alternate solution is provided by the use of copper based catalyst systems. The 5-iodouracil derivative shown in 7.77. was unreactive towards imidazole using either the Buchwald-Hartwig conditions or the copper(I) triflate promoted the carbon-nitrogen bond formation reported by Buchwald98 These latter conditions, however, were effective in coupling the iodouracil with a series of other amines (7.77.), The optimal catalyst system consisted of copper(I) triflate, phenantroline and dibenzylideneacetone (dba).99... 

I 13 Palladium-Catalyzed Aromatic Carbon-Nitrogen Bond Formation 13.3.3... 

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