Carbonylative Coupling of 1‑Iodoglucal and Amino Acids: Access to New Fluorescent Sugar Amino Acids

This study reports on the development of a palladium-catalyzed carbonylative coupling reaction for synthesizing glucal amino acids and fluorescent amino acid derivatives. A metal carbonyl was employed as a CO surrogate, avoiding the use of CO gas. Utilizing Pd-(OAc)₂ and triphenylphosphine, methyl esters of L-amino acids were coupled with 1-iodoglucal under optimized reaction conditions. Yields of up to 65% were achieved. The methodology was applied to amino acids with different side chains. Notably, the synthesized fluorescent derivatives containing stilbene moieties exhibited distinct absorption and emission properties with high fluorescence quantum yields.