Research in organic chemistry is strongly oriented towards the synthesis of compounds of potential medicinal use. We are therefore involved in developing synthetic methods towards a wide range of targets, ranging from small heterocycles and polyoxygenated systems, up to peptides and DNA analogues. For example, 1,3-dipolar cyclo-addition reactions are being used to prepare nucleotides with anti-AIDS properties. We are also trying to tackle diseases by probing the mechanisms of key biological processes; thus, the synthetic polycyclic peptide below shows similar properties to a bacterial enzyme transpeptidase, and may form the basis for designing a new generation of antibiotics. We are also developing host molecules to act as mimics for other enzymes, in order to understand their mechanism of action more precisely, or for use in medical diagnosis of diseases.