Hexafluoroacetone as protecting and activating reagent: New routes to amino, hydroxy, and mercapto acids and their application for peptide and glyco- and depsipeptide modifications

A critical and comprehensive overview on the synthetic potential of hexafluoroacetone (HFA) as bidentate reagent for the synthesis of new monomers for peptide, depsipeptide, and glycopeptide modification, which would be helpful to enlarge the synthetic repertoire, is presented. Application of HFA as a bidentate protecting and activating reagent to compounds such as Asp, malic, citramalic and thiomalic acids and homologues as well as iminodiacetic acid permits efficient site-selective mono-, di-, and trifunctionalization, saving steps compared to conventional methodologies.