In this issue, C. T. Walsh and B. S. Moore review enzymatic cascade reactions in biosynthesis. What are the four types of such reactions that lead to complex natural products? The Minireviews deal with enantioselective carbonyl catalysis enabled by chiral aldehydes (S.-L. You et al.) and the role of isotope effects in the history of the atmosphere and climate and the origin of life (M. Lin et al.). N. Blanchard and V. Bizet highlight the importance of acid fluorides in transition-metal catalysis.

In the Communications section, C. Yan et al. describe the tumor-microenvironment-induced degradation of ultrathin gadolinium oxide nanoscrolls for MRI-monitored, activatable cancer chemotherapy (see picture). A. H. Gröschel et al. succeeded in the template-free synthesis and selective filling of Janus nanocups. L. Di Bari et al. observed circularly polarized electrochemiluminescence from a chiral bispyrene organic macrocycle.

• Angewandte Chemie 21/2019: Cascading Chemistry,
  Angew. Chem. Int. Ed. 2019, 58 (21).