• amino acids
• halogenation
• phenyl sulfides

The synthesis of halogenated aminoacidic or peptidic compounds, due to their high biological activity, have gained a great interest in medicinal chemistry, above all for their relevance in preclinical and clinical.
A possible pathway for halogenation of these compounds involves the preventive synthesis of sulfur precursors. Indeed, S-phenyl group has shown to be a remarkable leaving group for the regiospecific attack of a halogen.
The aim of the research project presented in this thesis is the synthesis of sulfur-bearing peptides as a substrate for late stage halogenation. The main reaction is a selective addition, in alfa position with respect to the aminoacidic nitrogen, trough thia-Michael mechanism. The work is based on the attack of thiophenol or derivatives on the imminic group, formed between amine and aldehyde-derivate.
The reaction, induces the formation of a new stereocenter in the molecule, showing an evident enantiomeric or diastereomeric prevalence with up to 60% diastereomeric excess and good yields up to 70%.
The synthesis of these compounds lays the foundation for future late-stage halogenation studies.