A Very Short Route to Enantiomerically Pure Coumarin‐Bearing Fluorescent Amino Acids

No bulkier than a tryptophan or a tyrosine residue are the fluorescent coumaryl amino acids described. These building blocks can be synthesized rapidly with high enantiomeric purity and introduced readily into a peptidic sequence. Their fluorescence properties allow, for example, the investigation of the cellular localization of labeled peptides through confocal fluorescence microscopy (see picture).