Preparation of photoactivable amino acid derivatives
Débieux, Jean-LucDepartment of Chemistry, University of Fribourg, Switzerland
Bochet, Christian G.Department of Chemistry, University of Fribourg, Switzerland
28.05.2009
Published in:
Journal of Organic Chemistry. - 2009, vol. 74, no. 12, p. 4519–4524
English
A range of N-protected-α-amino acyl-5,7-dinitroindolines 3a−z were prepared in good yields from commercially available N-protected-α-amino acids 1a−z by a two-step sequence of acylation and intramolecular amide N-arylation. Subsequent photochemical acylation of the N-protected-α-amino acyl-5,7-dinitroindolines 3e,g,r afforded the corresponding N-protected-α-amino acid amides 22e,g,r (77−92%) under mild conditions. All these reactions occurred with complete retention of chirality as evidenced by NMR analysis. This scheme provides an attractive and alternative method to the conventional acylation of α-amino acids, especially in cases where the amide bond needs to be formed without the use of a coupling reagent.