Front Cover: Continuous Flow Spirocyclization Reactions: Towards Efficient Synthesis of Chiral Spiropenicillanates (Eur. J. Org. Chem. 42/2024)

The Front Cover illustrates the development of continuous flow spirocyclization of 6-alkylidenepenicillanates leading to chiral spiro-β-lactams through phosphine-catalyzed [3+2] annulation of allenoates and 1,3-dipolar cycloaddition with diphenyldiazomethane. The continuous-flow synthesis of spirocyclopropanepenicillanates through thermal ring contraction of spiro-1-pyrazolinepenicillanates was also included in the study. The reported methodology is a more sustainable approach for the scale-up production of compounds with significant biological properties in high yields. More information can be found in the Research Article by T. M. V. D. Pinho e Melo and co-workers (DOI: 10.1002/ejoc.202400689).