Synthesis of thiophenylalanine-containing peptides via Cu(I)-mediated cross-coupling.

Aryl thiolates have unique reactive, redox, electronic, and spectroscopic properties. A practical approach to synthesize peptides containing thiophenylalanine has been developed via a novel Cu(I)-mediated cross-coupling reaction between thiolacetic acid and iodophenylalanine-containing peptides in the solid phase. This approach is compatible with all canonical proteinogenic functional groups, providing general access to aryl thiolates in peptides. Peptides containing thiophenylalanine (pK(a) 6.4) were readily elaborated to contain methyl, allyl, and nitrobenzyl thioethers, disulfides, sulfoxides, sulfones, or sulfonates.