Organic Letters 2006-03-16

Expanding the substrate scope for C-H amination reactions: oxidative cyclization of urea and guanidine derivatives.

Mihyong Kim, John V Mulcahy, Christine G Espino, J Du Bois

Index: Org. Lett. 8 , 1073, (2006)

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Abstract

[reaction: see text] Oxidative C-H amination of N-trichloroethoxysulfonyl-protected ureas and guanidines is demonstrated to proceed in high yield for tertiary and benzylic-derived substrates. The success of these reactions is predicated on the choice of the electron-withdrawn 2,2,2-trichloroethoxysulfonyl (Tces) protecting group, the commercial catalyst Rh(2)(esp)(2) (1-2 mol %), and toluene as solvent. The frequency with which the heterocyclic imidazolidin-2-ones and 2-aminoimidazolines appear as structural elements in both natural products and therapeutically designed molecules confers these methods with a large number of potential applications.