Synthesis of non-proteinogenic phenylalanine derivatives by rhodium-catalyzed [2+2+2] cycloaddition reactions.

Non-proteinogenic phenylalanine derivatives were efficiently prepared by Rh(I)-catalyzed [2+2+2] cycloaddition reactions between enantiopure and racemic propargylglycine amino acids, with different protective groups, and diynes. Diverse substituents, including tags such as dansyl or dabsyl, were introduced onto the aromatic ring of the amino acid derivatives by selecting the most appropriate diyne reacting partners.