Enantiospecific Synthesis of Genetically Encodable Fluorescent Unnatural Amino Acid L-3-(6-Acetylnaphthalen-2-ylamino)-2-aminopropanoic Acid.

Fluorescent unnatural amino acids (UAAs), when genetically incorporated into proteins, can provide unique advantages for imaging biological processes in vivo. Synthesis of optically pure L-enantioner of fluorescent UAAs is crucial for their effective application in live cells. An efficient six-step synthesis of L-3-(6-acetylnaphthalen-2-ylamino)-2-aminopropanoic acid (L-Anap), a genetically encodable and polarity-sensitive fluorescent UAA, has been developed. The synthesis takes advantage of a high-yield and enantiospecific Fukuyama-Mitsunobu reaction as the key transformation. [ABSTRACT FROM AUTHOR]