Reactions of C-metallated Derivatives

The benzo-1,3-azoles (blocked or protected on nitrogen in the case of benzimidazoles) lithiate at the hetero ring 2-position. This allows reaction with the usual range of electrophiles the examples below show the introduction of iodine (followed by a palladium(0)-catalysed coupling with a boronic acid) and silicon (then the formation of a tris(benzothiazol-2-yl)phosphine). 

P-ToIB(OH)2, Pd(PPh3)4 PhMe, EtOH, N32C03 reflux  

The comparitively small number of examples so far available suggest that coupling chemistry can be just as important in the benzoazoles as in other areas of heterocyclic chemistry the two examples below show the use of a zinc benzoxazole and an indazolyl triflate.  

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