Access to α-Aminophosphonic Acid Derivatives and Phosphonopeptides by [Rh(P-OP)]-Catalyzed Stereoselective Hydrogenation.

The hydrogenation of N-substituted vinylphosphonates using rhodium complexes derived from P-OP ligands L1, ent-L1, or (R,R)-Me-DuPHOS as catalysts has been successfully accomplished, achieving very high levels of stereoselectivity (up to 99% ee or de). The described synthetic strategy allowed for the efficient preparation of α-aminophosphonic acid derivatives and phosphonopeptides, which are valuable building blocks for the preparation of biologically relevant molecules.

Halogen bonding effects on the outcome of reactions at metal centres.

Key findings regarding the effects of ligand preorganisation via halogen bonding on the outcome of reactions at rhodium are reported. An unprecedented halogen bonding-mediated oxidative addition of CAr-I bonds to rhodium with efficient formation of cyclometallated species deserves special mention.

XBphos-Rh: a halogen-bond assembled supramolecular catalyst.

The use of halogen bonding as a tool to construct a catalyst backbone is reported. Specifically, pyridyl- and iodotetrafluoroaryl-substituted phosphines were assembled in the presence of a rhodium(i) precursor to form the corresponding halogen-bonded complex XBphos-Rh. The presence of fluorine substituents at the iodo-containing supramolecular motif was not necessary for halogen bonding to occur due to the template effect exerted by the rhodium center during formation of the halogen-bonded complex. The halogen-bonded supramolecular complexes were successfully tested in the catalytic hydroboration of terminal alkynes.

Synthesis and biological evaluation of N,N'-squaramides with high in vivo efficacy and low toxicity: toward a low-cost drug against Chagas disease.

Access to basic drugs is a major issue in developing countries. Chagas disease caused by Trypanosoma cruzi is a paradigmatic example of a chronic disease without an effective treatment. Current treatments based on benznidazole and nifurtimox are expensive, ineffective, and toxic. N,N'-Squaramides are amide-type compounds that feature both hydrogen bond donor and acceptor groups and are capable of multiple interactions with complementary sites. When combined with amine and carboxylic groups, squaramide compounds have increased solubility and therefore make suitable therapeutic agents. In this work, we introduce a group of Lipinski's rule of five compliant squaramides as candidates for treating Chagas disease. The in vivo studies confirmed the positive expectations arising from the preliminary in vitro studies, revealing compound 17 to be the most effective for both acute and chronic phases. The activity, stability, low cost of starting materials, and straightforward synthesis make amino squaramides appropriate molecules for the development of an affordable anti-Chagasic agent.