Chiral cations have been used extensively as organocatalysts, but their application to rendering transition metal–catalyzed processes enantioselective remains rare. This is despite the success of the analogous charge-inverted strategy in which cationic metal complexes are paired with chiral anions. We report here a strategy to render a common bipyridine ligand anionic and pair its iridium complexes with a chiral cation derived from quinine. We have applied these ion-paired complexes to long-range asymmetric induction in the desymmetrization of the geminal diaryl motif, located on a carbon or phosphorus center, by enantioselective C–H borylation. In principle, numerous common classes of ligand could likewise be amenable to this approach.

Catalytic enantioselective Minisci reactions have recently been developed but all instances so far utilize α-amino radical coupling partners. We report a substantial evolution of the enantioselective Minisci reaction that enables α-hydroxy radicals to be used, providing valuable enantioenriched secondary alcohol products. This is achieved through the direct oxidative coupling of two CÀ H bonds on simple alcohol and pyridine partners through a hydrogen atom transfer (HAT)-driven approach: a challenging process to achieve due to the numerous side reactions that can occur. Our approach is highly regioselective as well as highly enantioselective. Dicumyl peroxide, upon irradiation with 390 nm light, serves as both HAT reagent and oxidant whilst selectivity is controlled by use of a chiral phosphoric acid catalyst. Computational and experimental evidence provide mechanistic insight as to the origin of selectivity, revealing a stereodetermining deprotonation step distinct from the analogous reaction of amidecontaining substrates.

We read with interest the paper by Maino et al. (1) which evaluated whether the expression of CD69 on lymphocytes might replace standard tritiated thymidine incorporation as a measure of lymphocyte activation and proliferation (LPA). We have used LPA as a screen after vaccination to determine whether further T cell studies (such as cytokine evaluation) are warranted, and were enthused by the possibility that an equivalent to proliferation could potentially be found as early as 4-6 h after obtaining whole blood or after thawing frozen peripheral blood mononuclear cells (PBMC). Since the majority of the results in that paper were obtained using mitogens, we carried out experiments to determine whether such rapid indicators of activation could be obtained in antigen-specific systems.We evaluated the response of PBMC (fresh and frozen) from 5 normal volunteers to antigens (candida 20 pg/ml, tetanus toxoid 5 flocculation units (LFU)/ml, and herpes simplex 10 pg/ml), as well as mitogens [phytohemagglutinin (PHA) 5 pg/ml, pokeweed mitogen 2.5 pg/ml, and concanavalin A 5 pg/ml]. Staining procedures followed the recommendations of the manufacturer. Equivalent percent rises in CD69+ values (corrected for unstimulated background fluorescence) were obtained whether the analysis included all acquired events or a lymphocyte subset defined by a light scatter gate.We confirmed the results of Maino et al. (l), observing that PHA was able to induce CD69 responses reproducibly within 30 min after addition to the cells, and other mitogens induced CD69 responses within 4 h, as previously published (Fig. 1 ). However, despite stimulating PBMC from five individuals with antigens which were shown to give excellent proliferation in simultaneous LPA experiments, no early (4-6 h) CD69 expression was seen. By extending the stimulation to 3 d, reproducible CD69 expression was seen in samples that also showed high proliferation (Fig. 1 ). Maximal CD69 expression was observed at 6 d for four different antigens in repeat experiments.Thus, the measurement of CD69 expression by flow cytometric methods could provide useful information regarding the cellular subsets which are activated by antigens or mitogens, and would avoid the radioactive waste generated by LPA. However, the rapid response seen with PHA and other mitogens does not appear evident in the context of antigen-specific stimulation.

Catalytic enantioselective Minisci reactions have recently been developed but all instances so far utilize α‐amino radical coupling partners. We report a substantial evolution of the enantioselective Minisci reaction that enables α‐hydroxy radicals to be used, providing valuable enantioenriched secondary alcohol products. This is achieved through the direct oxidative coupling of two C−H bonds on simple alcohol and pyridine partners through a hydrogen atom transfer (HAT)‐driven approach: a challenging process to achieve due to the numerous side reactions that can occur. Our approach is highly regioselective as well as highly enantioselective. Dicumyl peroxide, upon irradiation with 390 nm light, serves as both HAT reagent and oxidant whilst selectivity is controlled by use of a chiral phosphoric acid catalyst. Computational and experimental evidence provide mechanistic insight as to the origin of selectivity, revealing a stereodetermining deprotonation step distinct from the analogous reaction of amide‐containing substrates.

Malnutrition is associated with reductions in the number and function of T lymphocytes. Previous studies in the lab suggest that malnutrition may also impart a “super-quiescent” phenotype to T cells, perhaps affecting the efficiency of their migration within and between lymph nodes. Thus, the purpose of this study is to evaluate the effect of malnutrition on T cell migration in vivo and to characterize malnutrition-induced changes in the expression of proteins known to be important for T cell migration. To determine if malnourishment alters T cell migration in vivo, we compared lymph node entry rates of adoptively-transferred malnourished and control T cells in malnourished and control recipients. In agreement with other studies, control CD4+ T cells were more efficient than control CD8+ T cells at entering the lymph nodes. Interestingly, regardless of recipient diet, malnourished CD4+ and CD8+ T cells entered the lymph nodes at equivalent rates, suggesting that malnourishment eliminates distinct lymph node entry efficiencies for CD8+ and CD4+ T cells. We also found important differences in the expression of key proteins involved in T cell migration between malnourished and control mice. Overall, we found that malnutrition disrupts T cell migration including the distinct migration efficiencies of CD4+ and CD8+ T cells. An improved understanding of T cell-intrinsic changes that occur during malnourishment should enhance our knowledge of CD4+ and CD8+ T cell migration and shed light on how organisms adapt to malnutrition. Supported by NSF-MRI [DBI- 1920116] NSF-RUI [IOS-1951881]