Hyperpolarized isotope-labeled agents have significantly advanced nuclear magnetic resonance spectroscopy and imaging (MRS/MRI) of physiochemical activities at molecular levels. An emerging advance in this area is exciting developments of 15N-labeled...

Diazirines are an attractive class of potential molecular tags for magnetic resonance imaging owing to their biocompatibility and ease of incorporation into a large variety of molecules. As recently reported, 15N2‐diazirine can be hyperpolarized by the SABRE‐SHEATH method, sustaining both singlet and magnetization states, thus offering a path to long‐lived polarization storage. Herein, we show the generality of this approach by illustrating that the diazirine tag alone is sufficient for achieving excellent signal enhancements with long‐lasting polarization. Our investigations reveal the critical role of Lewis basic additives, including water, on achieving SABRE‐promoted hyperpolarization. The application of this strategy to a 15N2‐diazirine‐containing choline derivative demonstrates the potential of 15N2‐diazirines as molecular imaging tags for biomedical applications.

Rapid and efficient access to structurally diverse β-fluoroalkylamines is in high demand, with their wide presence and great importance in medicinal chemistry and drug development. Direct 1,2-aminofluorination of alkenes offers an ideal strategy for one-step entry to β-fluorinated amines from readily available starting materials. Yet the synthesis of valuable β-fluorinated alkylamines remains an unsolved challenge, due to the inherent incompatibility between electrophilic fluoride sources and the electron-rich alkylamines. We report an unprecedented, catalytic, three-component aminofluorination of diverse alkenes and 1,3-dienes, which has been achieved by an innovative copper-catalyzed electrophilic amination strategy using O-benzoylhydroxylamines as alkylamine precursors. The use of Et3N·3HF is also critical, not only as a commercially available and inexpensive fluoride source to enable effective fluorination but also as an acid source for the formation of aminyl radical cations for electrophilic amination. Mechanistic experiments suggest the involvement of aminyl radical species and carbon-radical intermediates under reaction conditions. This method features high regioselectivity and good tolerance of diverse functional groups and provides a practical and direct entry to a broad range of β-fluorinated electron-rich alkylamines. Synthetic applications of this method have also been highlighted by its use for the rapid entry to β-fluoridated amine-containing pharmaceuticals, natural products, and bioactive compounds.

α‐Vinylation of phosphonates, phosphine oxides, sulfones, sulfonamides, and sulfoxides has been achieved by selective C−H zincation and copper‐catalyzed C(sp3)−C(sp2) cross‐coupling reaction using vinylphenyliodonium salts. The vinylation transformation proceeds in high efficiency and stereospecificity under mild reaction conditions. This zincative cross‐coupling reaction represents a general alkenylation strategy, which is also applicable for α‐alkenylation of esters, amides, and nitriles in the synthesis of β,γ‐unsaturated carbonyl compounds.