Caiboxylic groups protection

Some examples for the introduction of amino protecting groups such as 2-(4-nitro-phenyl)ethoxycarbonyl (npeoc) or benzyloxycarbonyl (Z) were already given in the compilation of carbamates produced with imidazolium caiboxylates in Section 4.6.1. 

The phenyl group became a practical protective group for carboxylic acids when Sharpless published a mild, effective one-step method for its conversion to a carboxylic acid.1 It has recently been used in a synthesis of the amino acid statine, where it served as a masked or caiboxylic acid equivalent.2... 

Albericio F (2000) Orthogonal protecting groups for N -amino and C-terminal caiboxyl functions in solid-phase synthesis. Biopolymers (Peptide Sci) 55 123-139... 

---