Cover Feature: Metal-Free Dearomatization: Direct Access to Spiroindol(en)ines in Batch and Continuous-Flow (Chem. Eur. J. 10/2019)

Sustainable chemistry always seeks new synthetic tools. This study brings into light new catalytic properties of triphenylphosphine with the following features: fast, inexpensive, and broad applicability towards dearomative spirocyclizations. Triphenylphosphine has been applied for the synthesis of complex spiro(hetero)cycles in batch and employing continuous flow, a field largely dominated by transition metals. In the cover image, triphenylphosphine has been shown to act as a bridge between sustainable chemistry and the synthesis of complex heterocycles. More information can be found in the Communication by U. K. Sharma, E. V. Van der Eycken et al. on page 2442.