Transition carbon-heteroatom bond formation

Transition-Metal-Based Carbon-Carbon and Carbon-Heteroatom Bond Formation for the Synthesis and Decoration of Heterocycles... 

Maes BUW (2006) Transition-Metal-Based Carbon-Carbon and Carbon-Heteroatom Bond Formation for the Synthesis and Decoration of Heterocycles. 1 155-211 Maiti M, Kumar GS (2007) Protoberberine Alkaloids Physicochemical and Nucleic Acid Binding Properties. lO. 155-210... 

Transition Metal-Catalyzed Carbon-Heteroatom Bond Formations... 

Very few transition-metal catalyzed electroreductive carbon-heteroatom bond formations have been described. The electrochemical silylation of allylic acetates was carried out in the presence of Pd-PPha [131]. The electrosynthesis of arylthioethers from thiophenol and aryl halides [132] and the coupling of bromobenzene with dichlorophenylphosphine [133] were performed with Ni-bpy as catalyst. 

The transition metal catalyzed synthesis of seven membered and larger heterocycles attracted considerably less attention than the preparation of their five and six membered analogues. Typical examples in this chapter include the formation of heterocycles in insertion reactions, or through carbon-heteroatom bond formation. Although the formation of some macrocyclic natural products was also achieved in cross-coupling reactions they will not be discussed in detail. 

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,... 

R. Rossi, F. Beilina, Selective Transition Metal-Promoted Carbon-Carbon and Carbon-Heteroatom Bond Formation. A Review, Org. Prep. Proced. Int. 1997, 29, 139-176. 

Electrophilic aromatic substitution as a route to differentially substituted products is well established. The often forcing conditions, the incompatibility of this process with acid-sensitive functional groups, and the need for mild and selective syntheses have been the driving forces in the search for new methods of synthesis. A large range of methods has been developed over the past 20 years they include the trimerization of alkynes, the directed orfho-metallation, the benzannellation via metal carbenes, and transition metal-catalyzed carbon-carbon and carbon-heteroatom bond formation. Aromatic C-H activation, while still in its beginning stages, is another area of promise. 

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