Rh(III)-catalyzed C-H activation assisted by an oxidizing directing group has evolved to a mild and redox-economic strategy for the construction of heterocycles. Despite the success, these coupling systems are currently limited to cleavage of an oxidizing N-O or N-N bond. Cleavage of an oxidizing C-N bond, which allows for complementary carbocycle synthesis, is unprecedented. In this article, α-ammonium acetophenones with an oxidizing C-N bond have been designed as substrates for Rh(III)-catalyzed C-H activation under redox-neutral conditions. The coupling with α-diazo esters afforded benzocyclopentanones, and the coupling with unactivated alkenes such as styrenes and aliphatic olefins gave ortho-olefinated acetophenoes. In both systems the reactions proceeded with a broad scope, high efficiency, and functional group tolerance. Moreover, efficient one-pot coupling of diazo esters has been realized starting from α-bromoacetophenones and triethylamine. The reaction mechanism for the coupling with diazo esters has been studied by a combination of experimental and theoretical methods. In particular, three distinct mechanistic pathways have been scrutinized by DFT studies, which revealed that the C-H activation occurs via a C-bound enolate-assisted concerted metalation-deprotonation mechanism and is rate-limiting. In subsequent C-C formation steps, the lowest energy pathway involves two rhodium carbene species as key intermediates.

Filling in the gap: Label‐free, real‐time electrical detection of proteins is achieved with high selectivity and real single‐molecule sensitivity by using aptamer‐functionalized molecular electronic devices with single‐walled carbon nanotubes as point contacts.

An enantioselective [5+2] cycloaddition of vinylethylene carbonates and α-diazoketones was achieved for the first time by merging photoactivation and asymmetric Pd catalysis. The key to the success of this method is the enantioselective trapping of Pd-containing, 1,5-dipolar intermediates by ketenes, a class of reactive C2 synthons, which were generated in an in situ and traceless manner under visible light irradiation. Through this trapping, a variety of 7-membered lactones bearing challenging chiral quaternary stereocenters can be accessed in a facile manner with good efficiency and high enantioselectivity (up to 99% yield and 96:4 er).Communication pubs.acs.org/JACS

Detailed understanding of the signaling intermediates that confer the sensing of intracellular viral nucleic acids for induction of type I interferons is critical for strategies to curtail viral mechanisms that impede innate immune defenses. Here we show that the activation of the microtubule-associated guanine nucleotide exchange factor GEF-H1, encoded by Arhgef2, is essential for sensing of foreign RNA by RIG-I-like receptors. Activation of GEF-H1 controls RIG-I and Mda5-dependent phosphorylation of IRF3 and induction of interferon-β expression in macrophages. Generation of Arhgef2−/− mice revealed a pronounced signaling defect that prevented antiviral host responses to encephalomyocarditis virus and influenza A virus. Microtubule networks sequester GEF-H1 that upon activation is released to enable antiviral signaling by intracellular nucleic acid detection pathways.