In this issue, S. E. Denmark et al. review catalytic, enantioselective sulfenofunctionalizations of alkenes. How well understood is the structure, formation, stability, and reactivity of the key intermediate, thiiranium ion? The Minireviews deal with biomolecular densely grafted brush copolymers (N. C. Gianneschi et al.), transition-metal-catalyzed enantioselective C–H functionalization via directing groups (B.-F. Shi et al.), and oral insulin delivery platforms (W. Tao et al.). In an Essay, U. Rosenthal advocates vivid wording for the chemistry of group 4 metallocene complexes, and in their Editorial, E. C. X. Ang and C.‐H. Tan celebrate the golden jubilee of the Singapore National Institute of Chemistry and its partnership with Wiley-VCH.

In the original research section, H. Guo et al. present an organocatalytic asymmetric C(sp²)–H allylic alkylation (see picture). G. Delaittre et al. succeeded in a hetero Diels–Alder cycloaddition with RAFT polymers as a bioconjugation platform. K. Broch et al. found singlet heterofission in tetracene–penatacene thin-film blends. C. Richert et al. investigated how the enzyme-free release of nucleotides from phosporamidates depends on the amino acid.

• Angewandte Chemie 45/2020: Overcoming Barriers,
  Angew. Chem. Int. Ed. 2020, 59 (45).