Comparison of 1,2-Diarylcyclopropanecarboxylates with 1,2,2-Triarylcyclopropanecarboxylates as Chiral Ligands for Dirhodium-Catalyzed Cyclopropanation and C-H Functionalization.

Dirhodium triarylcyclopropanecarboxylate catalysts (Rh2TPCP4) are sterically demanding and capable of controlling the site selectivity of C-H functionalization by means of C-H insertion with donor/acceptor carbenes. This study compares the structures and reactivity profiles of dirhodium triarylcyclopropanecarboxylates with dirhodium diarylcyclopropanecarboxylates. The absence of the third aryl group makes the catalysts less sterically demanding and lacks a well-defined preferred conformation. The catalysts have a greater tendency for inducing C-H functionalization at tertiary C-H bonds versus their triaryl counterparts but are generally not capable of achieving high levels of asymmetric induction. These studies confirm the critical requirement of having at least three substituents on the cyclopropanecarboxylate ligands to have well-defined sterically demanding catalysts capable of high levels of asymmetric induction.

Potent Rifampicin derivatives can clear MRSA infections at single low doses when concomitantly dosed with Vancomycin.

For a number of years, antimicrobial resistance (AMR) has been a critical issue for humanity. Drug discovery efforts have been very limited and the spread of bacterial pathogens has over-run our traditional arsenal of antibiotics. Bacteria can involve to evade compounds that can halt their rapid growth. The authors have discovered a potent macrocycle derivative that when dosed concomitantly with the standard of care (SOC) antibiotic vancomycin, can clear methicillin resistant Staphylococcus aureus (MRSA) infections. In addition, we have probed the lead compounds in Salmonella typhimurium bacterial strains. In vitro, in vivo, and ADME data have been included to stress the virtues of this new antibiotic.

Regio- and Stereoselective Rhodium(II)-Catalyzed C-H Functionalization of Cyclobutanes.

Recent developments in controlled C-H functionalization transformations continue to inspire new retrosynthetic disconnections. One tactic in C-H functionalization is the intermolecular C-H insertion reaction of rhodium bound carbenes. These intermediates can undergo highly selective transformations through the modulation of the ligand framework of the rhodium catalyst. This work describes our continued efforts towards differentiating C-H bonds in the same molecule by judicious catalyst choice. Substituted cyclobutanes which exist as a mixture of interconverting conformers and possess neighboring C-H bonds within a highly strained framework are the targets herein for challenging the current suite of catalysts. While most C-H functionalization tactics focus on generating 1,2-disubstituted cyclobutanes via substrate-controlled directing group methods, the regiodivergent methods in this paper provide access to chiral 1,1-disubstituted and cis-1,3-disubstituted cyclobutanes simply by changing the catalyst identity, thus permitting entry to novel chemical space.

Erratum: Regio- and Stereoselective Rhodium(II)-Catalyzed C-H Functionalization of Cyclobutanes.

[This corrects the article PMC7233328.].