Chemoenzymatic synthesis of the two enantiomers of 7-azatryptophan
7-Azatryptophan is an unnatural α-amino acid with a very potent fluorescent activity. It is used as a vehicle for probing the structure and dynamics of proteins and peptides. Diastereoselective alkylation, diastereoselective protonation and enzymatic resolution have been tested for preparing enantiomerically pure 7-azatryptophan.